@gunnarhj, the main reason not to use Wayland on NVIDIA is that it doesn’t support hardware acceleration of X11 apps (most apps and all games). They are rendered in software on the CPU, so that’s a significant step backward. But NVIDIA has a fix on the way. Also, I am advised they’re making the next driver release (470) even more Wayland-friendly. So those are the two main things we’re waiting on right now. You can find the active list of issues here.
We have bug 1887652 open for that.