It's a bit unfortunate because most of the listed commands are indeed equivalent to Git commands. To give an example of new capabilities, in Git, you can't do the equivalent of
jj rebase -r 'mine() & diff_contains("TODO")' -d 'heads(@::)'
in any reasonable number of commands, which will
1) find all of the commits I authored with the string `TODO` in the diff
2) extract them from their locations in the commit graph
3) rebase all non-matching descendant commits onto their nearest unaffected ancestor commits
4) find the most recent work I'm doing on the current branch (topologically, the descendant commit of the current commit which has no descendants of its own, called a "head")
5) rebase all extracted commits onto that commit, while preserving the relative topological order and moving any branches.
Furthermore, any merge conflicts produced during the process are stored for later resolution; I don't have to resolve them until I'm ready to do so. (That kind of VCS workflow is not useful for some people, but it's incredibly useful for me.)
1) find all of the commits I authored with the string `TODO` in the diff
2) extract them from their locations in the commit graph
3) rebase all non-matching descendant commits onto their nearest unaffected ancestor commits
4) find the most recent work I'm doing on the current branch (topologically, the descendant commit of the current commit which has no descendants of its own, called a "head")
5) rebase all extracted commits onto that commit, while preserving the relative topological order and moving any branches.
Furthermore, any merge conflicts produced during the process are stored for later resolution; I don't have to resolve them until I'm ready to do so. (That kind of VCS workflow is not useful for some people, but it's incredibly useful for me.)