I think this is great. Only limit of git is I can't imagine "git blame" works. It would be nice to know who voted for and against each patch. Git isn't structured for collaborative commits.
But getting the entire country's law into git is already an impressive feat.
Not git, but Congress actually does have quite a bit of data digitized. A random example[0] -they even provide XML. The Congress data is going to give you all bills - many of which do not pass, so a different mission than this project.
[0] https://www.congress.gov/bill/118th-congress/house-bill/4818
Git isn't structured for collaborative commits, but community-wide conventions kind of "patches" support for it on top of the git message body, via "Co-Authored-By: name <name@example.com>" which IIRC most platforms support, and the convention itself initially comes from Linux kernel development.