Indeed, a Fossil repo is actually a SQLite db, one you may as well open and tinker with (at your own risk :). By the same token, it's just as easy to back these repos up, as much as copying the db-file. Or automatically push to a remote. Cron job -- done!

Of course, mishaps happen, bugs too. Blaming SCM is easy, blaming no-backup habits, well, that's personal.

Fossil does get progressively more potent, I can attest to this on my user experience at least from v1.19 to v1.35. Many convenience features are added, yet core remains stable.