Almost all Matrix servers seem to require at least an email address. A better option would be XMPP, as most servers only require a username and a password to register. It's also the IETF internet standard and a lot less bloated than Matrix.
I only track the dotfiles which I actually write, not the generated ones. So it's not so different from code. Desktop programs which generate intransparent config files suck. I only wish there was a good way to synchronize my Firefox using git. I know there is user.js but it all seems like a mess to me.
I also rarely want old versions of my code, but I still use git. A very nice feature, besides the essential backup quality, is to synchronize dotfiles between machines and merge configs together if they diverge.
People like shiny things. They should build on the existing internet standards, and make a shiny XMPP client. Instead we get yet another incompatible protocol.
In the game I will create this afternoon, a JAB can be bought and sold for 1.25 USD, making it the more powerful currency than the US dollar.