Yeah, the rear ones I don’t think are attached to anything and can usually be pretty floppy and useless. The front ones are usually attached pretty well and I’ve seen them use them a lot. Of course, tons of dogs do tear them but dogs tear other toe nails too.
In my experience with beagles hind dewclaws are attached about 85 % of the time. When removing at 3 days it is essential to also remove the little nub of bone they are attached to. I'll probably jinx myself with this, but I routinely trim dog nails and have to deal with torn toe nails very infrequently. For me it comes down to proper maintenance of the dogs' feet. Something that is essential for hunting hounds.