I think you are right about the DAG. Once I understood what the high-level data structure of git is, many branch related commands immediately made sense and it was suddenly very easy to use. Many of my colleagues haven't taken the time to learn that and continuously struggle with basic commands.
Honestly the DAG isn't the whole story. The distributed nature also adds a twist that makes things entirely difficult, and the obtuseness of the commands is yet another layer of difficulty. People have every right to expect git commit to commit their changes to the remote repo. And it very well could, but it just doesn't happen to. Similarly you can't tell me with a straight face that notion of having to 'git add' a file you just deleted in order to be able to commit that change is somehow intuitive. I could go on and on but the point is knowing the DAG is hardly the end of the story.
I agree it's not the end of the story, but without that knowledge, learning git is almost impossible. Even with DAG knowledge, some commands are hard to remember.
