Whatever it takes to get you moving, but it is a little self-deceptive to ignore or replace natural incentives for fitness with artificial incentives of mere shadows on a cave wall. Perhaps the real world is a little boring, but it has the distinct advantage of being authentic.
Good for you and congratulations, but it was most likely due to your own hard work along with dietary adjustment, so you need not diminish your accomplishment by giving a device as much credit as you give yourself. The Watch really didn't do anything but keep time; you yourself did everything and filled the time.