I have no horse in this race but it seems to me that you're not understanding their point. JJ has a different workflow that doesn't have a concept of a staging

I have no horse in this race but it seems to me that you're not understanding their point. JJ has a different workflow that doesn't have a concept of a staging area, for one. The fact that you don't need to make a WIP commit may not be a game-changer for you, but it demonstrates that the abstractions it provides more accurately represent the "editing a previous commit" workflow. If that's not useful to you, fine. But I think it's valuable to have tools that 1) integrate into existing (git-based) systems with low friction and 2) provide abstractions more suitable for the work I tend to do on a daily basis.