When you say you never needed LSP, do you mean you've tried it and found no benefit to having it, or do you mean you're doing just fine without it? (Because its possible to do just fine without it yet still find significant benefit to having it).
What LSP does for me is instant documentation integrated into the editor and getting constant feedback if you get it wrong (at least from a typechecking perspective). I guess that in many cases, you can get something similar by having a documentation window open on the side as well as automated unit tests in a second terminal re-running on every save.
I have tried using it few times but I didn't see much benefit of using it, I am mostly working with python/django/javascript/react and by now most of the common functions I already know, so I didn't see much use of it and tbh it felt a bit distracting to me when a big hover definition came when I am typing something.
The times when I don't remember how something works, usually I have to go the stackoverflow answers/documentation to read on how it works, maybe try it out a few times in the shell, before writing the code. For typechecking and errors I have been using ALE and it does give a warning if there's something wrong and this setup is working fine for me.
What LSP does for me is instant documentation integrated into the editor and getting constant feedback if you get it wrong (at least from a typechecking perspective). I guess that in many cases, you can get something similar by having a documentation window open on the side as well as automated unit tests in a second terminal re-running on every save.