I thought this about Eagle's[1] project storage switching to XML; I figured it would allow us to store projects and libraries in git and easily branch / merge changes etc.
It was a nightmare. XML does not work well in git.[2] I even thought I could resolve some of the issues by sorting elements so they'd be in a consistent order, but none of the elements had guuids or anything to allow me to do that.
I have had that thought in the back of my head for a little while with my own eagle projects, thanks for making the mistake for me!