One of the strengths of open source is its diversity of technical solutions. It's a feature, not a bug.

Before git, there were other open source version control systems, and they still work. For example, sometimes a centralized repository is the right tool for the job, and subversion is still there.

Fossil is cool. Almost no one uses it, aside from sqlite themselves, so it sort of feels like a roll-your-own VCS. But it works for them, and I suspect it would work for a lot of other people too.

sqlite has some interesting philosophical foundations, and that makes it an unique project. :)