Vim has a learning curve like nothing I have ever used. I have been using it for the better part of 10 years and still learn new things about it all the time.
The main draws for vim for me is that it is on all* Unix/Linux based systems and doesn't require a gui.
The example given by u/biffbobfred is a good one being able to do a find and replace.
A feature I would mention vim can do is macros. The idea is you can record your steps in a process then tell vim to repeat it as many times as you want. The examples listed here explain it pretty well.
If you want to get to know vim I suggest starting with vim adventures (I have no idea if the paid content is worth it). Also install MacVim and set it to be your default editor for all the things that make sense (basically anything that isn't opened by Word/Pages).
Vim has settings and plugins to make it much more functional. If you would like more explanation there let me know.
*typically vi or vim are installed by default. vi is inferior, but still passable.
edit: spelling is hard
Short evolution of Vim (main "family"):
ed --> ex --> vi --> (old) Vim --> (modern) Vim `--> Neovim
mvim
is MacVim - just Vim for MacOS, which follows MacOS conventions.
It gives you a Mac window wrapper around vim -g
. One can customize the Mac menu bar at the top, the window toolbar, use GUI tabs, it adds an “open in MacVim” service to the services menu, allows one to assign trackpad gestures including force touch, will change style for light/dark mode, etc. I’m using it for Vim; I like it. And if you don’t like it one can customize it via startup files until you do.