Even if I enjoy leetcoding and I do, there are tons of things I would rather do before that, and that are far more useful, such as building and working on side projects.
So to me leetcoding is a waste of time and less fun than actually building something, having other people use what you have built. And there is infinite things to build there and learn.
I get that. I only do medium and easy problems for a reason. Hard problems are hard and I want to solve it over morning coffee. :)
Then again, I'm sure all of my leisure activities are a waste of time on someone's metric.
I probably learn more from the comments than the problems though. People post lots of interesting idioms and it's interesting to me to see how others codify various standard algorithms. Especially across languages.
So to me leetcoding is a waste of time and less fun than actually building something, having other people use what you have built. And there is infinite things to build there and learn.