> With Jujutsu, you'd instead use jj split to split the working copy commit into two commits.

This is more confusing? Often times when debugging/writing a fix I would have extraneous code that I wouldn't want to commit. With an index I'm always sure if what I commit, but with this workflow you have to keep track of such stuff all the time and if you forget that stuff makes it in?

Not to mention that another benefit of an index is being able to change commits and git replaying your working diff.