What's wrong with vim over ssh/mosh? I was taught emacs by a grad student back in college and the ability to be fully productive on any server where I can install emacs has been a huge benefit to my career. I can't imagine vim is much different in that scenario.
Sure, but if the goal is to teach programming, I think vim massively confuses a beginner. vim is hard for beginners, famously so. Something like VSCode, used as a remote text editor, is trivial and familiar to anyone who has used at MS Word. I agree it should be introduced, but there's definitely some cargo cult around vim and "the old ways".
As you say we're teaching programming. The ability to pick up an unfamiliar tool and get to know it on the fly is critical and the only way to develop it is practice.
That said, maybe there is no right answer here. I imagine the instructor's broader approach will make the difference, not which editor they make the class use for assignment three :)
Most of the time you'll be editing config locally on your laptop and it'll get pushed to the servers via config management or whatever.
Your laptop is the place for your tricked-out IDE with 27 plugins
By contrast, VS Code needs to inject itself, plus any plug-ins, over to the remote side. Wanna know how long that can take if the link isn't decently fast?