I use Wayland exclusively, and I'm on up to date Arch. I'm talking about issues like screenshare issues with software, XDG desktop portal screenshare randomly breaking, steam notifications started positioning wrongly, steam's search stopped working (not 100% sure if those two are Wayland)...
I also tried running a game in game scope with HDR enabled, experimenting with options and env cars I found online, but it just didn't work. It was a sample size of one, but it was one game I wanted to play with friends, so I gave up in favor of just playing.
I also don't use MPV - I tried testing HDR with it, and it probably worked fine, but I don't have the right media to test it. (Side note: I should try mpv more seriously, but I haven't needed a video player much in general)
An extra annoyance is the fact that the LDR colors are quite off with HDR enabled on Plasma. I suspect this is the fault of the display or configuration, but it's still something I'd have to spend time researching and fixing, only to barely get any use out of it.
I haven't tried setting up steam itself in gamescope, but wouldn't it be limited to one window then? Could try it just to experience an HDR game, but otherwise it's a bit of a deal breaker.
You might be right about it being for enthusiasts in the first place, but I feel like there's a lot of people who will just pay up for a good screen that includes HDR, and on Windows I'd imagine you can just turn it on and start getting HDR from various sources - something that will surely become possible on Linux, but will take a while longer.
All that said, I'm not saying this to shit on Wayland or the developers' work on HDR. Not long ago HDR was something that just wasn't possible, and people were whining it'll take another 10 years at this rate. I'm excited to see the next update on this, as well as stable wider adoption, but that's the thing - that's something I'm anticipating, not something I'm gonna be using now.