> I find a bit annoying when projects don't use GitHub... I need to set up a new account to interact with them

The same is true in the other direction ("Ugh, this project is hosted on GitHub and I now need to set up an account"), with one major difference: compared to other sites which tend to just accept username + email + password for setup and username + password to log in, it's a huge PITA to set up a GitHub account in 2025 and to log in to an infrequently used account from a logged out state. GitHub won't let you get away with using it in such a simple way.