I’ve never understood that argument. That’s like saying you prefer to walk everywhere because your car (which you already own) might not always have a full tank of gas.
Much of the reason Vi(m) is still in use today is because it’s guaranteed to be on pretty much any *nix box. When it’s 3AM and you’re trying to rewrite /etc/lstab from scratch and the network won’t come up… there’s no way you’re installing emacs or nano.
Honestly, ex mode would be such a good idea … if it didn’t clear the entire goddamn screen when it started up! The whole point of using a line editor is that it shouldn’t take up the entire screen.