A different way of doing the same thing for text editing, on which both are great. I use evil-mode just because of muscle memory from vim.

I have been using a jetbrain IDE recently and surprisingly, the vim plugin is pretty decent. So knowing vim lets me use both the IDE and emacs with less friction. A team mate uses jetbrains and emacs side by side, there's some option in the IDE to launch an external editor. Jetbrains emacs keybindings suck.