I mean that's a fair question, because I feel like mostly the advantages are, hm, not "theoretical" because it's an actual advantage, but not something you'll really encounter day-to-day. better security for example. but generally who cares because if I interact with something malicious I'm probably owned anyway.
originally I was interested in it because of fractional scaling, but I think that works in X11 for the most part now?
at this point it's mostly about using the bleeding edge stuff so I can help find problems. I do find that when it works it works very well, and the experience of using a Wayland desktop is less wonky: fewer weird rendering glitches when dealing with multiple monitors, connecting and disconnecting my laptop from a dock, etc. I find this works better with Wayland, but I wouldn't say "so much better that you must move to it today" if you're happy with what you have.
similarly full-system stability has been better, and I have fewer crashes that take down everything, I feel. it's perhaps subjective though: I've been running it for so many years maybe all I'm experiencing is that the software I run has become better in general.
so: I don't think it's a night-and-day life-changing experience or anything, but it does feel modern and stable, and it's definitely where things are heading so why not get used to it now, and help to improve it, is my thinking.