Interesting the history is varied for such a simple tool.
I am but a lowly mouse/GUI user so rarely have to dwell in a shell, but I learnt the basics of vi in my 1st year of university and never forgotten. Gotten me out of many a pickle being able to reliably edit a file quickly.
Neovim supports the mouse by the way.
I'm a GUI user too but using helix-mode (like vim-mode but IMO more intuitive) in my GUI editor, zed, gives me the benefits of both.
Simple tool? Visual text editor is probably the most complicated piece of software in coreutils.