I recently upgraded my gaming PC from Win10 to Bazzite with Wayland, and my use cases are primarily streaming to a laptop and to a quest 3. I don't find these very niche use cases tbh. The challenge was, unfortunately, getting around Wayland. It may be a security feature, but to me it feels a bit like making a car safer by removing the wheels so you can't crash it. It could ask for permission or let me whitelist applications like Steam, Sunshine and ALVR, but it doesn't. I ended up plugging a dongle into the HDMI port, so there's always a monitor "on" and it now works perfectly fine, but I would have been happier if I didn't have to do that, like Windows before it.

Maybe there are good reasons for Wayland to be the way it is, but my experience is that it's unnecessarily limited, it's in the way and "the rest" doesn't have these problem (Windows, Xorg, ...) so I'm not particularly fond of Wayland, even if it does a lot of things fine and it is quite stable (in my experience).

Yeah, large parts of the not supported things are nice when you are doing them intentionally, but easy for an attacker to abuse against you and you won't notice until it is too late. It is annoying when you want to do something and Wayland won't let you, but in the modern world we have plenty of attackers trying to abuse our computers to do evil things and we can no longer rely on trust. (we never could - X was always big in universities where there is always some student doing annoying things, though that was annoying and not otherwise harmful to life like today attacks)

Other parts are things that are on the list only because X did it that way in 1985 - nobody actually does that in X but you can find a line item and scream that Wayland doesn't do that.

Most of the rest are things that can be supported but need a some more work, and progress is being made. Most are things most people don't even need/use - though of course if you are the rare person who uses them wayland won't work for you.

The remainder is NVIDIA who is way behind. We have known they are not a good linux citizen for more than 15 years now though, so I can't have sympathy for those who buy their products. (yes I know they are the fastest in other ways, but their linux support as always been a hack)