Nothing, there is nothing wrong with nano. There are what I will call vim purists who think using anything but vim is sacrilege. I’ve been using nano, and it’s predecessor Pico forever and while I can use vim if I need to, I don’t hate myself enough to do so.
Yes yes, vim good, nano bad. And rather than have discourse on the matter I’ll call you all fascists and claim you support genocide. Definitely an adult thing to do, good job you.