Don't get me started on "Microemacs" which, while it shipped on the Workbench disk, was barely usable either.
Don't dare to say anything more bad on (micro)emacs or I'll turn this thread in a classic emacs vs. vi war thread. And if you think the infighting on amiga.org is bad; I assure you you ain't seen nothing yet...

I suppose "vi" is somewhere in the sweet spot of being quick to launch and (given enough available brain capacity) quickly allows you to commit keystroke sequences to muscle memory. Yes, it's a weird design, but so is the standard keyboard layout. If you learned touch-typing, it's amazing how well you can use that weird layout at great speed. It doesn't work quite so well with more heavy-weight editors such as the original "emacs".
I've been told that the weird design was actually thought through: it was to reduce the risk on mechanical typewriters with the next letter getting stuck on the returning previous letter.