For people who ask, "why use text-only editors like vim or Emacs, when I can use a full GUI IDE?": One of the reasons I haven't seen mentioned much is: I'm a touch typist, and I hate having to switch between mouse and keyboard! I have to take my attention off the screen. Slows me down. Disturbs my concentration. With Emacs, I can work for hours without ever having to hunt for the mouse, or without even having a mouse…
To add to this: yes, full blown IDEs have shortcuts but they are hard to explore, counter-intuitive and hard to extend.
cmd+shift+a opens a command palette with every possible command in the IDE. It matches as you type the name of an action, and every action has a keybinding shown to the right (if it exists).
Every relevant button generally has keyboard shortcuts right on them.
And pressing cmd+e opens a list of gui interactions you've made so you can repeat them (things like focusing buffers, clicking on a file in the project file tree, etc.)
Basically, if you know cmd+shift+a, you're golden for learning commands and key shortcuts.
In comparison, emacs/vim are pretty awful. I've done a few tutorials of each and while I could have spent more time learning them, JetBrains makes it stupid easy to start learning the editor.