Leetcode started around 2015
But once upon a time these leetcode interviews made a ton of sense. Just getting your program to run at all was basically a leetcode exercise.
see for example: https://arstechnica.com/gaming/2020/03/war-stories-how-princ...
I have my war stories too. It was fun but frustrating. Definitely not as productive as today.
Early 2000s internet was kind of like that too. The web was huge relative to what we had to work with and there wasn't the kind of products/services available then so asking leetcode stuff had a logic to it.
Admittedly, that's not where we are now for most programmers so it makes sense that the interview process should adapt.
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.
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.