I use it for lots of projects, spanning years of work, including commercial projects with ~20 devs. Those projects aren’t public, and I’m sure lots of other people do use it that way. It’s still not going to rival the install base of git.
I use it too. I like to self-host my commercial projects, and when I decided to move away from Subversion about seven years ago I did consider Git, but the ease of self-hosting Fossil made the choice for me. Just plug it into apache httpd and off you go. Some time later GitLab became available, so now I'm also running a GitLab instance. But the Fossil server has much smaller footprint and is easier to manage.
The ease of use/management is a big deal, and to an extent I think it falls out of technical design decisions (proper database for repo storage that fully, easily, obviously allows first class multiple checkouts of a single repo instance). Others are philosophical design decisions, most of which I think I like, some I think I don’t, and others that just aren’t in place yet. Key is it’s nice to work with, and if I’m doing development/management, as much as possible I want it to be an enjoyable experience.
