There are some tasks I do infrequently enough I can't remember the paths, commands, and options... but my history always saves me. So when I know it's full of useful stuff, and especially when moving a bunch of files/functionality to a new place, I tend to create a copy of my .bash_history in another, non-hidden file.

Of course such renamed files wouldn't have been part of this analysis, so it doesn't exactly explain why files exactly named .bash_history are in Github. (For that, I'd surmise many people make an entire project-specific login directory git-versioned.) But it does hint why someone might intentionally want to remember their history in version control.

Done intentionally, it strikes me as a potentially valuable reproducibility, auditing, and training practice – documenting what was done around the time of other file evolution, making it easier for someone else to help out in a pinch with full context.

Versioning their home directories to git, and doing it in-place instead of linking specific files from a ~/.dotfiles or similar.

(See https://github.com/technicalpickles/homesick for an example of how to do it right.)