I've actually used reverse grip a bit in my training.
My coach said it's good for 2 things.
1. Tricep strength
2. Teach you to keep your elbows in.
I've never, nor would I ever do it in the smith machine.

Bigmac, do you think it would be so harsh on the rotators is you used a barbell like me?
I've never had rotator issues, but then again, I can't even bench 300 lol