Do you mean Wrist bands or wrist braces?
IF it's that braces, it is my understanding that they are used to help keep one's wrist in place. It is a good training tool, but has found its way into becoming a neccessary bowling accessory. I've had mine on for the past couple of weeks to help get my wrist into the position that I want it to, I think I'm going to bowl without it this week, mostly because I think the muscle memory is now established.
Also if your wrist can't handle the position you like and the ball weight that you have, a brace get help support the weight of the ball as well.
As for wrist bands, if you want to wear them I suppose you could. You'd look like a tennis player bowing to me. But whatever floats your boat.
As for your elbow, I don't know. I know there is a band you can put around your arm just before your elbow. It is supposed to lessen the strain on your elbow. It might help you out with your injury or pain, but most people I see use it, use it to help compensate for their muscled swing.