Apple Watch control is here with the current beta as of this date. I've been using it on an Apple Watch 3 cellular and it works great. Turned my phone off, and just used the watch app on its own, it even works then, so then I can ditch the phone if I'm out and about (not sure if it needs cellular network or just bluetooth). I also have the WiFi module but not sure if the watch app needs that.
(although it sometimes doesn't wake up on the Apple Watch. I have to swipe left and touch the icon for my Sesame to wake it up, swipe back, then it will connect)