And you can even edit the content you stage, so that you can stage something different, than what is in the working tree. Having different content in the index vs. working tree is the feature of the index, which I think JJ just doesn't support?
jj doesn’t support it in the sense that there’s no special index feature. You can use a workflow where you have a commit represent the index (and that’s basically the most common workflow). This means you don’t need a separate feature, you just use the tools that slice and dice any commit with your “index”.
