Hmm... well i think it could be used for say the crotch or head region, someplace were it could be very bad if damaged.
I think it could also be potentially useful for practicing flips or something. something that wouldnt necessarily impede technique, but could prevent you from, say, landing on your knees and busing the crap out of them. you would know how you landed and you could tweak from there, but it wouldnt hurt you.