I'm not sure there is much of a function other than to be an ornament. Theoretically, it's supposed to keep the front apron from flying up in the wind, but they're rarely heavy enough to make any difference. You're not supposed to use it to pin the 2 aprons together because you may end up tearing one of them, so there's not much going for it other than it's weight, which is usually not much more than an ounce. They are the best opportunity you have to add some flash to your ensemble, though, other than the plaid broach, which most people don't wear most of the time.