Perhaps not essential but using git offers great benefits for almost anything you do, publishing to crates.io or otherwise.
It need not be complicated either. Git is kind of huge and intimidating with a billion features. You will read all over the place about branching, merging, rebasing etc, etc. But typically I only use a handful of simple commands:
I find that even for small experimental codes once it's past a day or so's work it's worth stashing it in git and then github/bitbucket/local git repo.
It helps greatly keeping versions straight of course. But what I like is the way I can mash on code experimentally and if it turns out to be silly idea and everything is broken then "git checkout" and boom I'm back to my last know working state.
It helps greatly when I want quickly pull code to different machines/platforms and test it there. It's easy to move the code. It's easy to know all your copies everywhere are the same version.
All in all it's about organizing chaos and the peace of mind that brings. Rather like the type system and borrow checker in Rust. "Hack without fear" as someone said.