Jujutsu has "first class conflicts", but it's different from Pijul's "theory of patches". As far as I know, the other big stuff like "working copy is a commit" and the "operation log" (which allows for `jj undo`, safe concurrency, etc) is not present in Pijul. The approaches to Git interop are very different.
One thing I really appreciate is that you can run `jj new master` at _any_ time to drop what you're doing and start a new change. The way jj handles the working copy, conflicts, and visible heads means there's just no need to think about uncommitted changes, unfinished conflict resolution, detached head, etc.. So many things that would get in your way just can't happen.
Part of this that hasn't been mentioned is that the mirror is thicker than you might expect. The observatory's website says 12.5 inches (though it will vary somewhat across the curved surface).