I doubt its for drummers. Seems to be marketed towards prep-school conservatory musicians that want to be fashionable. Nifty, but our phones can do that same thing...but cool someone is thinking about developing good time, we drummers encourage that
As for the visual thing, I remember showing my drum teacher the Tama rhythm watch and boosting how you can visually see the lights. He quickly said "train your ears, not your eyes" and I think he was correct. Unless I'm doing some sequencing thing in a live setting with a band where it isn't audible, the visual was not the right tool for internal time...at least that is my experience, teacher here may do differently. But then again, looking at the visual didn't hurt either, as long as not depended on.