I can see the behavior being useful in some cases (and not a _super_ common cause of mistakes once you learn it), but the issue for me is mainly that it's surprising and easy to get bitten by before you learn it. This describes git entire UX as well in my opinion: the underlying model is very powerful and generally pretty sound, but the API for it does a poor job of making it clear, and generally you have to make a lot of mistakes on the way to learning how to use it properly.
Git is conceptually very sane and logical. But the UX is indeed (still) terrible.
But a lot of people seem to complain about the complexity of the underlying concepts. That makes no sense to me as the concepts are complex because the problem at hand is complex. Also it makes no sense to me that people are constantly crying for a new tool even they have obviously issues with understanding the problem space and all requirements. A new tool would not make all this complexity go away! It could at most try to "hide" some of the complexity by introducing magic. This wouldn't be helpful at all as magic is way worse than bad UX, imho. Bad UX is bad UX you can deal with it. But when magic goes wrong all bets are off and you're usually in deep trouble.
This looks like people would argue to rewrite the back-end (some propose form scratch!) even only the front-end needs some face lift…
I think the only potential improvement I can think of to the underlying model is that a patch-based system does seem like it would alleviate some of my pain points, but the UX for that hasn't exactly been fully figured out either; last time I tried pijul, it certainly seemed compelling feature-wise, but I wasn't able to figure out everything I wanted to do with it easily. It also would mostly just be a quality of life improvement for me at this point too; git is fully capable of doing everything I need it to, but sometimes I might have to google a bit to figure out how exactly to tell it what I want.
