Awesome, cheers. It also seems to encourage merges over linear history (I guess because the history of "bookmarks" is deemphasised), is a linear history still achievable?
I think it's exactly the opposite and the mental model of branching is counter-productive with jj. It's much more in line with trunk based development and the idea of managing 'stacks' of changes (kinda like merge trains where multiple smaller PRs in turn depend on each other).
If you had multiple people working on a branch and only some were using jj, then those not using jj would likely have issues with all of the rebasing and force pushes that happen behind the scenes to keep the history clean.
If you were to enforce linear history (like in GitHub) and used rebase merges exclusively then I think it's ideal, especially in terms of reviewing smaller, incremental changes rather than huge pull request diffs.
If you had multiple people working on a branch and only some were using jj, then those not using jj would likely have issues with all of the rebasing and force pushes that happen behind the scenes to keep the history clean.
If you were to enforce linear history (like in GitHub) and used rebase merges exclusively then I think it's ideal, especially in terms of reviewing smaller, incremental changes rather than huge pull request diffs.