I think the point is to not leave yourself in a position where you're not proficient with any text editor at all.
This is an actual issue. Some students show up at college without ever having written a line of code and without knowing how to open a plain text file, make changes to it, and save it.
It doesn't matter that much which one you learn. If you already have an opinion about which one you like better, you're already where you need to be and can skip the section on editors. If you learn vim and don't like it, you can learn a different editor.
Having only very rarely needed to use vi/vim or emacs, I'd say it does very much matter which editor(s) you learn. If you learned BBEdit, DOS Edit, TeachText, or WordPerfect 1.0 for UNIX, you'll be lost it vi/vim or emacs.
What you'll think you know about "how editors work" will be actively harmful. I've seen and heard of people resorting to pressing the computer's reset switch when they can't figure out how get out of a 'real' textmode editor whose behaviour defies all commonalities. And good luck getting to the man-page if you can't get out of the editor.
When I've needed to use one of those, I fortunately had been provided exact steps or had a 'real user' who could help me. I've had a few goes at the man-pages ages ago (which were not installed on one or two systems!), but paging through them just made 'real' editors seem even more like "not a usable editor" to me. Too dainbramaged by having grown up with 'intuitive' editors that give more affordances.
