There’s nothing stopping you from using separate changes to emulate the staging area if you want.
I can, but I don’t need to.
jj has nothing I need, so it would be changes for the sake of changes. I’m not saying it’s bad, but people do need to realize that their struggles are theirs, not the whole world.
That is, in essence, the "squash workflow": https://steveklabnik.github.io/jujutsu-tutorial/real-world-w...
The big differences are that the jj approach gives you a commit message for the staging change, and lets you jump to some other commit without extra steps.