Clearly there are people who will play games on their watches. I'm not one of them, not yet anyway.
Saying that I have played around with ideas for a couple of, kind of, mini game extensions for my games. While I do find them entertaining, I still wouldn't spend the time playing them myself.
I just don't see the watch as a suitable platform for gaming, small screen, uncomfortable playing position for any length of time and the bloody screen keeps switching off. Which is why I'm not incorporating any, yet.