One of the best parts is the bindings! They are present in most shells/terminals, GNU readline-based programs, and even native macOS text field. If you're in a terminal or using a terminal-based program, there's a good chance pressing any of the core Emacs keybindings does what you expect it to.
It's probably largely just habit at this point, but the keybindings are a big part of what keep me with emacs. I honestly have no idea how people navigate text/code with default windows keybindings. That they work by default in many other contexts is a really nice bonus. Most emacs binding emulation modes I've seen for other editors don't support even basic things like "C-<space> C-n C-w", which is basically a non-starter for me.
