Kong Duck/Climb Tech Rollinlock/WC Ropeman USES Question

I do not know much about these devices, nor have I ever used one.  Would it be possible, practical, to use one of these small devices as an auto block while rapping?  Can you hold the clamp open, as you would with pressure on a prusik, and then release it to remove gear, rest, etc.? Also wondering if these things would destroy a rope like ascenders?  could they be used with a dynamic rope?

Thanks

and sorry if this question is silly.

They can be used with Dynamic rope. Ascenders if used properly do not damage rope. 

Using them to autoblock while rapping would not work very well though, you would have to hold it open, not lock it open - it would be really awkward. Also you cannot just "release it" like you can with a grigri, once they are weighted you need release the weight to move the cam. You would be better off using a chord or sling as an autoblock. Or a shunt if want a mechanical device. The autoblock would stop you to retrieve gear and you could tie an emergency knot w/ biner to rope or wrap around leg several times to go hand free. 

All of those would be horrible choices for a backup to a rappel set up.  

None of them would work on a double strand. 

All of them would be hard to keep open. 

They won't destroy a dynamic rope if used for ascending.

The rope man will not work as a back up as you need to hold the cam out rather then squeeze it in to release. It works great for acsending and will not destroy rope like a jumar. They are however very small and difficult to attach and use with gloves. It sounds like you need a Petzl shunt. It is designed to be used as a auto block and also works as an ascender. It can also be used on double rope from 8-11 mm

Other posters covered it, definitely not a backup for raps. I will add that I have used a rollnlock as my primary device to rope solo on a dynamic rope (just haven't got around to purchasing static). It works well and has caused no appreciable sheath wear (note I also keep it taught to my chest harness, so falls are quite short).

Thanks for the feedback, I have never used any of these but I was watching a video of the kong duck and was thinking that if it worked as a descender as well it might a clever device.