> text files are by far the minority (at least by size)
Well yeah because text files are small. Thinking text files are insignificant to games because they are small is a really dumb perspective.
> Yet still people try to use git for version control in game projects just because it is the popular option elsewhere and git is all they know.
Or perhaps it's because it works really well for text files, which are a significant part of most games, and because the tooling is much better than for other VCS's.