Vi is fine. It's superior and to bare ed - The Standard Editor*, when you don't have anything else available. I made much of my living coding vi 7 years in -80's. And I still use vi, when emacs is not there or system has so little memory that emacs is too much. Which is usually with a embedded systems or some old Unix on single mode fixing unbootable system.

*) https://cs.wellesley.edu/~cs249/Resources/ed_is_the_standard...