I honestly can't say I've ever seen a non-techie expand a window to full screen using the green button on macOS. I'm not sure why, because in theory, I agree with you.

In my experience supporting Mac users, it's about 50/50. I think a lot of them have been conditioned to not maximize windows because it hides everything else, and they don't understand how to get back to their other windows.

I don't maximize windows because it means a 1 second delay, as for some reason Mac OS still does the hardcoded workspace switching animation even for that. Which means entering/leaving fullscreen in a video player is also delayed every time. I don't get it, not even the accessibility settings can disable this waste of time.

It does weird things in multi monitor because dragging a window on top of the newly “maximized” window somehow does not work

One issue with windows maximised with the green button is if you have more than 1 window of the same app: you might alt-tab to the app, but cmd-` is not switching to the other window of the same (while id does if not maximised.