Old BD 4.5 (red)

I have a new #5 and older #4 (no thumb-loop), and have come across an old red 4.5 for sale.  
How does the range of the 4.5 fall in with the two cams I have?  Any value in adding it to the rack, or does the overlap between the #5 and #4 make the 4.5 unnecessary?
I've read a bit, and know that there was a change in the size of the 5 and 4 a few years back, but have never used a 4.5 or had one to compare against what I have.

The general advice that I’ve seen is that unless you absolutely love Indian Creek then you’ll never find a “need” for it. Don’t bother. 

IF you like climbing at Beacon, you can walk the old 4.5 on the second pitch of Dod's, and there is a place for it on Dastardly as well.

In my experience the size of the old #4.5 (red) feels too similar to new #5 to seem particularly useful as an in-between size. But the old #4 (purple) does actually feel useful as a half size between new #4 and new #5. I wouldn't buy the #4.5 and instead would just rather have another new #5

I'm sure someone disagrees with me :)

The red 4.5 is listed as Generation=Old and Entity=SS Camalot.
Looks like the current purple completely overlaps the old red range.
https://camparator.com/compare/cam/selection/?i34=1&i764=1

it’s basically a #5

I own both and its basically a 5

There are some places where the 4.5 is exactly the right size, where neither a #4 or #5 (new or old) is quite right. The Lost Arrow Spire is known for this.

I should start a company just make .15 .25 .35 .45 .66 .825 1.5 2.5 3.5 and 4.5

Call it,  I'll go in where others won't   

Sounds like it's too close to the current 5 to be worth bothering about.
Thanks, all.