why are "obligatory" grades only a thing in Europe?

So all these grade threads got me thinking.
I've noticed many route reports in Europe specify the grade and the obligatory grade (I've seen these in Dolomites and Costa Blanca; and a few more places online).
Obligatory grade is basically the A0/1 grade for the non-aid pitches, i.e. the minimum grade you have to climb to finish the route "french free". For example, Costa Blanca route on Peñon de Ifach is listed in a few places as 6c+ (6b obligatory), because the crux pitch is typically free climbed but you can aid to make it easier; otoh the routes on the same wall that have typically-aided pitches are given a combined grade e.g. 6a+/A1.

Being that I climb for fun and don't need to prove anything, I find this system very helpful, especially for sport+trad routes where there can be a huge difference at the same grade between the crux being a committing affair on bad gear vs a closely bolted sport pitch.

However I've personally never seen this obligatory grade mentioned for any route this side of the pond.
How come?

quite a lot of the (mulipitch)routes in the Dolos and elsewhere in europe were opened a long time ago, using a mix of freeclimbing and aid( mostly A0/A1..) , and were repeated for years in the same style. later on, when those routes were free climbed, usually both grades where mentionned, as there were still people doing them in the classical style, the same is done with the routes freed on the big walls in Yosemite for exemple, routes still mostly climbed using aid (Nose etc..)In routes put up as free climbs, the obl. grade often gives  you an idea about how committing the hardest sections are, say, a 7a obl  in a route graded 7a or 7a+ is a different story than an 7a / 6a obl. It gives you an idea comparable to a 5.12 crack which you can basically protect like bolt ladder or a runout wall climb of the same grade in TM bolted on lead. That info also comes quite handy in a place like the Verdon gorge where bailing is sometimes not an option.. This is also a good indicator of the crowds you'll have to expect...if max diff= obl, you'll have the route for yourself;)

Seen it  a fair  bit.  Ancient  Art  comes to  mind.  

I think this is only applicable to long  routes. towers etc.  Things with a summit. not much point in  getting on a single pitch rig unless its a spire  with the intent of faking it. getting to a summit is a whole different prospect. 

Ile show you whats cool? in Cody the MP description might mention that its 8+ but many people grab the draw at the crux.  certainly the comments mention it.

Sergey Shelukhin wrote: Being that I climb for fun and don't need to prove anything, I find this system very helpful, especially for sport+trad routes where there can be a huge difference at the same grade between the crux being a committing affair on bad gear vs a closely bolted sport pitch.

However I've personally never seen this obligatory grade mentioned for any route this side of the pond.
How come?

Some good answers above, but I think you'll see this mostly on longer, more committing routes, where you can't aid (unless you're really good with hooks and have them).  We don't have many places like that in North America.  As someone said these are older routes, often bolted, but they are NOT sport routes and the bolts are too far apart to A0.

For example, you do 8 or 9 raps onto a 1,500ft long route in the Verdon.  If you get one or two pitches from the top and can't make the moves, you're screwed because you can't go up.

Rapping the route is chancy because some of the rappel routes do NOT go to the bottom, you'd be stuck on a ledge overnight (at least).  And even if they do, rapping to the bottom and walking out through the tunnel is a total fucking epic.    It's gets done, but never willingly.  

So the obligatory grade is the grade you NEED to be able to climb tired, hungry with sore toes and fingers in order to get out before dark.  

seen  stuff in the desert with 2 grades. Ancient Art 5.9 A0 or 11a  is a prime example.  seen a few others out there. we have a few here in  the north east on longer multi pitch.    certainlt Yosemite must have these rateings. the free rating and the aid rating. 

I see it quite a bit in Washington. Sometimes you have to read a bit into the route description in a guide book. Because The large majority of the routes that have obligatory grade, are roofs that used to be tricky to protect like the bone in Leavenworth is 5.9 but if you read the description it was put up as 5.7 /A1 route same as same as fiddler on the roof at mt erie 5.9 or 5.7A1. I think lots of route here in the US were rated like this but people kept climbing it in a free style and the aid bit slow fades away. Just read deeper in the guide books and you'll notice it more, And you'll really appreciate what some pioneers did before cams.

There's an earlier thread

https://www.mountainproject.com/forum/topic/116070982/lost-art-of-french-free-falling-a-climbers-gamble?page=2

on this subject in which I wrote

"Back in the day that was a sensible way used to describe climbs with an isolated crux or two and the rest of the route being easier. For example, in W.W. Fricke’s “A Climber’s Guide to Rocky Mountain National Park” and in Scott Kimball’s and Chip Salaun’s “That-AA-AI-ATAH”, the climb Guillotine (mountainproject.com/route/1…) is rated 5.7, A1 or 5.9 (Fricke) and 5.10 or 5.8, C1 (Kimball-Salaun).
Modern guidebooks rate it 10c, which is less informative. There’s a few feet of 10 finger-crack at the start and then it never gets harder than 5.8."

Thank you for all the great answers! Commitment aspect makes sense, although is not a big problem in Costa Blanca (having bailed off two routes with a sacrifice of one biner total (the other route already had a bail biner) ;)).
With regard to the the original style, and scaring people off it did seem that the European climbing culture is a bit more relaxed in these respects.

For routes like the ones in Yosemite, the 2nd grade seems to be for more or less full-on aid; whereas in Europe it's more like, well I'll try this overhang, and if all else fails I can pull on a draw in this one spot.
Sometimes there are tips in route description, but that is not common and kinda obscure in my experience. E.g. what is the obligatory grade for Levitation 29? (rhetorical question) There is lots of varied and sometimes vague info, but if it was in Europe given the nature of the route there'd probably just be a number.

But yeah it mostly makes sense why now :)

Nick Goldsmith wrote: seen  stuff in the desert with 2 grades. Ancient Art 5.9 A0 or 11a  is a prime example.  seen a few others out there. we have a few here in  the north east on longer multi pitch.    certainlt Yosemite must have these rateings. the free rating and the aid rating. 

Nope, these are NOT prime examples of "obligatory".  Obligatory: Required as part of a routine course of action    Required  is the key word.

 If you can't climb 11a then you can aid it with gear, so it's not required.   If you can't aid A0,  you can rap down.  So climbing is not required.  

But in the Verdon, for example, it can't be aided, certainly not at A0 (maybe A3 or 4).  It's often smooth unblemished limestone.   And rapping down is a serious epic, especially when you don't know if you can rap to the bottom.   Hanging exhausted at the end of your ropes, 30m from the ground, in the dark...  And even if you do get through the tunnel without headlamps and encountering Shelob, you're still a long way from the car.

Deven Lewis wrote: I see it quite a bit in Washington. Sometimes you have to read a bit into the route description in a guide book. Because The large majority of the routes that have obligatory grade, are roofs that used to be tricky to protect like the bone in Leavenworth is 5.9 but if you read the description it was put up as 5.7 /A1 route same as same as fiddler on the roof at mt erie 5.9 or 5.7A1. I think lots of route here in the US were rated like this but people kept climbing it in a free style and the aid bit slow fades away. Just read deeper in the guide books and you'll notice it more, And you'll really appreciate what some pioneers did before cams.

Was gonna say, a version of this grade system is pretty common in the Cascades. Blake Herrington's book mentions an alternate grade for routes that can be French freed at a lower grade on a good chunk of the routes included in his guide. 

Kyle Elliott wrote:

 Blake Herrington's book mentions an alternate grade for routes that can be French freed at a lower grade on a good chunk of the routes included in his guide. 

If I remeber right he gives liberty crack 3 different grade 5.13+ or  5.12/ A2 or 5.9 A2. I really like his guide book he is honest and makes things approcable for us mortals!

I’ve seen Time Wave Zero as 12a or 11a/A0

Also this is common on big walls that are more often aided than freed. Ex: The Nose 5.8 C2 or 13d