The main thing that makes it more powerful imo is that you can accomplish insane rebases with 1 command that would be really difficult with git.
Like let’s say you have 4 separate PRs in review that have no dependency on each other. You then work on new stuff on top of an octopus merge of all 4. You are exploring different approaches to a solution so you have several anonymous branches where you have tried different things. You want to rebase on master, so you just run jj rebase -d master. All 4 PR branches, the octopus merge, the anonymous branches, they all get rebased with that 1 command. If there are conflicts the first class conflicts mean that you can fix the conflicts whenever you want. If one of your experimental anonymous branches is in conflict but you are unlikely to go with that approach, just leave it in a conflicted state unless you change your mind that you want to actually go that direction.
Like let’s say you have 4 separate PRs in review that have no dependency on each other. You then work on new stuff on top of an octopus merge of all 4. You are exploring different approaches to a solution so you have several anonymous branches where you have tried different things. You want to rebase on master, so you just run jj rebase -d master. All 4 PR branches, the octopus merge, the anonymous branches, they all get rebased with that 1 command. If there are conflicts the first class conflicts mean that you can fix the conflicts whenever you want. If one of your experimental anonymous branches is in conflict but you are unlikely to go with that approach, just leave it in a conflicted state unless you change your mind that you want to actually go that direction.