Pijul looks cool, but "replace hard to understand directory content snapshots with easy category theory" isn't a compelling proposition outside of maybe the ML/Haskell community.
The main point of Pijul is, you never have to think about categories when using it. It's just a sort of Git where you almost never need to branch (the equivalent of a Git branch in Pijul is just a patch), merges are always deterministic and easy to understand, cherry-picking is the default, and works even for conflict resolutions.
Git is the C++ of version control. Of course it’s powerful. Of course it can do everything. And of course it’s a huge frustrating footgun with error messages that rival any c++ template compiler error.
The problem is that we have made it a de facto standard so it’s hard to replace. Even if a much better VCS emerged tomorrow, it doesn’t help if there isn’t support in large issue trackers, CI/CD systems, IDEs and so on.
I have great hopes that pijul will be the better git. But again, it’s the tooling and ecosystem that matters, not the qualities of the vcs itself.