The big selling point of emacs, really, is that it's command driven - and you can go write the commands yourself. All the boring little tasks that you do while writing normally? Changing variable names in multiple places, if you have largely formal constructs you use a lot-
if (dah de dum de dah) {
} - that sort of thing. You can even insert a formal construct and then have parts of your typing mirrored out in it.
You can give yourself multiple cursors with their own buffers so that you can work on multiple lines with similar constructions if you're making pattern type alterations to things.
Any problem that's structured to follow the same sort of pattern, you can probably make the text editor do them for you.
That's more along the lines of why people might want to use emacs. There's a lot of dead-time involved in typing things out that can be automated if you've the tools.