These are good for protecting the skin on the hands. However, if you have any concerns about your wrists or protecting yourself over long periods of training, you might want to invest in a pair with more foam padding.

That would depend on the athlete, age, weight, etc.. and the coach, but i would not recommend them personally for anything other than bag work. The coach holding the mitts will almost surely regret doing so if the athlete punching has any sort of pop to his punches.