For last 4 years I'm using Jujutsu exclusively, and it is just here. I forgot what staging is and only recalled it when it was mentioning in the post.
So I agree with siblings: because better frontend exists than git cli.
The only one that was truly intuitive to me was Envy/Developer. It only really made sense because we used it in Smalltalk but I really liked the packaged nature of change sets that it modeled.
Git is nowhere near the worst of these. SVN, hands down a cranky and unreliable dumpster fire was the worst.
With git at least you can get way with using a surprisingly small subset of features if you regularly merge before doing your pull request.