vi is basically gonna be on every Linux based machine until the end of time. Nano usually needs to be installed, which in corpo environments, you may not have the ability to do that. I made my peace with vim for sysadmin stuff or simple changes like editing yaml files. Vi also has some pretty good features out of the box which are good to learn.

Vim is the main modern project under active development. vi is the original software from old UNIX. On most Linux nowadays, vi opens vim in vi emulation mode.