This little guy actually serves a few good purposes. If your sportsbike has a round front brake reservoir, it prevents leakage and brake fluid sweat from dropping onto your valuable paintwork. It is also the best form of sunscreen to prevent the white plastic from breaking down and cracking due to UV radiation.
Apart from that, they actually do provide some decent wrist support during everyday operations and the odd game of tennis. And, of course, they can be used as a serious fashion statement to stand out from the crowd.