The big downside is having to install neovim. Good old vim is in macos, git bash on windows, any random vm you’re thrown into… I also use the vim plugin for intellij et al, but I use vim on all the raspberry pi’s, weird windows boxes with some issue, and so forth. It’s already everywhere and neovim isn’t.
Then again, most of my time these days I spend in JetBrains Clion with Vim emulation, as it is much better suited to the kinds of projects that I currently work on than Vim or Neovim ever was. So take my opinion on Vim vs Neovim with a grain of salt.