Well, it depends. In practice, I think the number of branches is similar. In theory, the number of possible branches is much, much greater (arguably infinite)

Well, it depends. In practice, I think the number of branches is similar. In theory, the number of possible branches is much, much greater (arguably infinite) for git. Commits have their own metadata, so just amending creates a new commit. Patches are immutable, and there's no independent artifact like a commit that incorporates the current set of patches. Furthermore, darcs (and I assume pijul) absolutely let you make multi-file patches.