The first time I found myself in nano was when testing a distro fifteenor twenty years ago. I had to edit some files and it was the only available editor. The damn thing was a horror to use. I still have no idea who it caters to. I haven't had to use it since though.
Dunno what you used, but nano is literally a text editor that may be simple simple but it just works. Shortcuts are shown to the user, buttons work like you expect them to (arrow keys, ESC, shift, etc)
With vim you open it and if you haven't read 5pages of doc you won't even be able to close it again. I see that its useful for power users, but for casuals who just want to edit a config once in a while nano is absolutely the way to go imho