Everything I'm about to say, I say as a Vim/Evil user who avoids IDEs like the plague. I like Vim. I like composing commands on the fly, I like modular editing, I like that I can magically format CSV files with quick macros, and I like jumping around my editor like I'm Spider-Man. Heck, I swapped out my window manager with EXWM and Evil just so I could use Vim-style modular commands everywhere.
But learning Vim isn't related to learning how to program. In that context, it's a pointless distraction.
Be honest -- when was the last time that you or anyone you know had a programming assignment at work and came back to scrum a week later saying, "I'd have finished this, but navigating around my editor just took up too much time?" >95% of programming is going to be bottle-necked by the speed you think, not the speed at which you can edit text.
So it's like forcing all of your students to learn Dvorak, or to submit all their written work in cursive. Undoubtedly a few students will thank you for it at the end of the class because some people do get real value out of learning those skills -- but just as many of them will say you wasted their time, and they'll be right. I write in cursive too; it's an objectively faster, more pleasant way to take handwritten notes. That doesn't mean that learning cursive has anything to do with learning to write books.
To any professors on HN reading this: if you're teaching a programming class, please teach programming. Because if students just wanted to learn something new, or to be forced to struggle with something outside of their comfort zones, there are a lot of cheaper ways than college they could do that.
Even with that goal -- a programming professor can't come up with any outside-the-box assignments more related to their subject than "learn Vim"? I can't fathom that kind of lack of creativity in a field this broad.