I admit my beta-ness here.
I use them on tons of stuff. Barbell pressing (to keep hands from slipping) and even light back exercises and yes...dumbell curls. I agree with Adonis on this one.
My forearms are like my calves...got a genetic gift so I don't care if either of those bodyparts gain more size. They've got all they need for my liking.
Plus, for those of you guys who practice jiu-jitsu, you know it's a way better grip workout than anything in the gym. I do 3x/week, and my grip is trashed. I don't need to hammer it more in the gym.
Flame away!
EDIT: when I was powerlifting, I never strapped on anything. That was 8 long years. So maybe that's why I don't care anymore. I put my time in.