It's not that the supposed concepts that are hard, it's that it has one of the messiest interfaces and set of documentation ever devised for a software.
And there are hardly any settled concepts, the terms it used came to be as it was developed, and can have different definitions in different parts of the documentation.
If you consider it simple I'm very seriously concerned about your software engineering output
A lot of the problems people have with git are actually problems with bad workflows. You can argue that git should support arbitrary workflows but that's like arguing a garbage truck should support offroading.
Software engineers benefit from good tools as well, and having to spend months to get to know a vcs well enough doesn't benefit anyone
Would would be the one good git workflow, in your opinion?