I don't know if it's common but I generally don't like to be bad at my hobbies. I like it when I can do things well. I've been learning the piano recently and striving to play more difficult songs is what makes it fun.
I think music is a good example of sometimes you need to not have fun to have fun. Practice isn't really fun, but if you can put up with it you can have a lot of fun. So you can say that the not fun parts are part of the fun parts because it's what gives you the payoff. But when people then go and send you a Suno generated song, and say it's better than yours, it is them devaluing the "not fun" parts you had to put up with. I've had people do similar things to code projects I've done. It's a real buzz kill.
I also really value when musicians critique my songs, even when I feel defensive about it. Because then it's not about them devaluing my time, it's about them helping me grow, and they know how it feels to go through that process.
>I've been learning the piano recently and striving to play more difficult songs is what makes it fun.
And are you going to give up learning piano because now AI can just generate piano music better than anything you can ever produce? No? Then what you're doing is a proper hobby, which contrasts with the OP who feels their efforts are no worthless because AI can just do it better. That's not really a hobby; it's a job.
(Apologies if I'm missing your point)
I do kind of understand it when it comes to programming, though. Hobby-like side projects often felt like they had some utility down the line, even if not directly applied. It's fun to show others what you've accomplished, to show off, maybe land a job from being noticed, etc.