Let's be clear, it is a wrist housing for your GoPro, but that doesn't mean it has to be used on your wrist. The idea behind the wrist housing is that you can, eh, wear the camera on your wrist. The camera can tuck down so it sits flat on your wrist then you can pop the camera up and get the shot. It is designed to be able to fit over gloves, jackets, or tight against your skin. The beauty is, it can be fit to other things as well. GoPro themselves make suggestions like kayak paddles, windsurfing masts and more. We like to ride bikes though, so those things don't help us. But they do seem to work great on the downtubes and headtubes of some bikes.
This housing is very simple to use and attaches quickly and easily. No matter how tired you are from conquering the King of the Mountain on your favorite Strava ride you will still be able to easily get a quick selfie at the summit without another calorie burned.