I've just noticed in the "Sound and Vibe" menu there is a setting for "Haptics".
I don't remember it being there before - maybe it was introduced in recent firmware. I'm currently on Beta 18.21.
Anyway, it doesn't seem to do anything. I assumed it would probably make the watch vibrate when the touch screen is touched. Can someone confirm this is the expected/intended behaviour?
And could someone check if this setting exists in 17.xx firmware and see if it works?