The standard Lisp use for generated symbols is to provide a way to reliably avoid name clashes during macro expansion.
I'm not sure if that qualifies as a practical use in the out in the wild or just a practical way to fix pain (e.g. CPP nonsense) that you can see out in the wild.
They seem to be being used mostly as immutable constants for readability--which kind of fits with normal use, right? I'm just trying to see if there's anything else here I'm missing.
So, that sort of makes sense if you were to use them as keys in the new Map and Set objects...but I again, I can't help but notice that I haven't felt their absence yet.
Thanks for the reference about CL make-symbol. Is there a practical use for this we actually would spot in the wild, or do I need to go up on the mountain with a copy of The Art of the Metaobject Protocol?