I've seen some skilled unix/linux users use joe instead of vi(m) or nano. Why would they prefer using it over the provided alternatives?
It's easier to learn than Vi, faster to start than Emacs, and more powerful than Pico/Nano (e.g. it has ctags support for programming).
But it's unlikely to be installed everywhere, so you should still know the basics of Vi and Emacs.
It uses WordStar key bindings by default. This was a common word processor in the early 80s, and I even used it in the early 90s. When I first got into Linux, I looked around for an editor that made sense to me, and hey, there it was.
I imagine that some other now-skilled Unix/Linux users followed the same path, because Linux arrived just at the end of WordStar's effective life. So, one of the reasons is simply "timing".
Modern versions have syntax highlighting and other fancy features, so I haven't bothered to switch away.
(I know how to use