I can see where those things would be interesting for students learning software development, but not everyone who uses git is doing that type of development. To be fair, I am coming at this from the standpoint of someone who uses git for science, rather than software development. Yes, I use it to track changes in code, but vast majority of that code is scripting analysis procedures (so knowing about internal data structures does not directly help me do my job). I also use git to track changes in LaTeX manuscripts. So, while your first point is arguably universally applicable (that knowing the internals would help me use git), the second point does not apply to everyone.

I am not suggesting that all tutorials should jettison an early discussion of the git internals, but merely suggesting that including such a discussion early on, may not be appropriate for some audiences.