Sapling source-code management system - no staging area?

Okay, this might be such an extreme necro it qualifies as actually weird but trying to find words for a reply to this has been niggling at my hindbrain all this time. That acknowledged,

Git is: a dag of snapshots plus annotated tags in the object db; local refs; and an index for tracking work on (often constructing new) snapshots. That's it. Everything else, everything else, is in whatever's-useful-in-your-work territory.

There's software design that starts with some perceived ideal/need and jumps straight to abstractions which are then explained and implemented, this is the root of the "implementation details don't matter" view of software, the "abstract principle first" sort of design that views any behavior not covered by the abstraction as aberrant, egregious.

Then there's software design that starts with basically a data structure and asks "what use can be made of it", it might start out as a design for a perceived need but abstractions are just ways of talking about the effects you can get.

What I'm saying is: Git's the second kind. Anything you can do with a dag of snapshots and re-hanging local labels, you can do with Git. The people who want definitive and elegant abstractions tend to express distaste for this, they'll call Git's UI a leaky abstraction and get more pejorative from there. And I think that's where they're entirely missing the point. Git's a tool, a data structure plus commands to work with it. The Git interface uses abstractions to talk about the useful things you can do, not to define what's proper.