> it tries to hide the index and thus encourages bad habits in git users.
I'm curious what you mean by this. What are good & bad habits wrt the index?
It makes sense the index is there for conflict resolution, and it seems really convenient for interactive adds & rebases. But I could imagine implementing those things without having an explicit staging area. Are there other more important requirements for the index? It mostly seems like a convenience that it's exposed, but not something that provides either more safety or better practice.
Many VCSs that predate git don't have an index because they don't need one, and having one wouldn't encourage better habits. Git has an index and rebasing almost entirely as a result of it's strict enforcement of lineage, which older VCSs didn't have. In Perforce you can create and manage multiple changes before you push, and you can push them in any order. Because git enforces order, it basically needs rebase and an index to make using git sane. In that sense, these things can be seen as a UI disadvantage over other VCSs. Of course we know there are much bigger advantages that come with strict lineage, so we learn to stage, rebase, etc.
What other benefits does the index provide that I'm missing?