I'm unfamiliar with hg, but git is incredibly easy to use. I alias common commands to shortcuts, so git commit is gc, git push is gpsh, git status is gs (I'll never run GhostScript from the command line), etc.
Any time I start a new project, even if it's just an experiment with a new library that will never see daylight, the first command I type after mkdir is git init.
Seriously, don't do any coding without version control. Once you've tried git, you won't want to (Mercurial is probably similar).
The reason is probably because you make it sound like setting up a VCS is such a big deal. Hg or git require literally running a single command.
It also seems like you think the concept of branching in hg or git has a lot of overhead too. Again, it is literally one command to create a new branch and one command to merge or revert that branch when you are done. I don't understand why you think one needs a working MVP in order to use branches.
Any time I start a new project, even if it's just an experiment with a new library that will never see daylight, the first command I type after mkdir is git init.
Seriously, don't do any coding without version control. Once you've tried git, you won't want to (Mercurial is probably similar).