Every time I see examples of people getting JJ to do something it doesn't do natively, it turns out JJ has a good, well thought out interface for extension. It's a huge credit to the JJ devs that it's so naturally extensible.

jj looks very interesting and the hipster in me wants to adopt it, but my muscle memory is wired to Magit, I am not even an Emacs user, but I reach to it just for doing git stuff. So far none of the frontends for jj comes close.