There are some really major deficiencies in Xorg that aren’t present in Wayland. The main one that made me switch was proper support for variable refresh rate, and the ability to mix and match any fixed or variable refresh rate displays you want.
It’s a super common use case to have a primary monitor with high refresh rate and VRR, plus one or two cheaper monitors that don’t. Xorg doesn’t really support that at all without some really hokey tricks that severely impede usability.
Proper sync support is another one. Yes, you can set tearfree in X but the implementation is crap. You’ll still get tearing in a lot of programs and at least in my experience, it introduces a pretty significant and perceptible input lag, far more than needed to eliminate tearing.