This is such an amazing idea. I've already thought of two things it might be useful for: a) No headphone cords when running. b) No headphone cords if you fall asleep (just in case they get wrapped around your neck)
Also great for kids of age to carry a house key - Bracelet key, no more putting keys in your pocket. Great for jogging and wearing pocketless pants. Dude I'm 14 and I still lose house keys I need this badly.