If your AR was your "toy" like a sports car or something, why not "trick it out"? It's your gun, the options are there, I say if you want it go for it. I don't see it any different than pistol grips and mag extensions and heat shrouds for shotguns. So what? If you like it do it.

But me personally, I like the look of the ones that remind me of a Colt M-16