I get what you mean, but git is basically a tool for manipulating the .git directory (and a working directory checkout).
I think understanding what .git dir contains and represents is as important as understanding the tool.
It's not like you need to understand how the tool works internally, or how it's built.
Analogy would be that you want to understand how to use a hammer, sure, but also the characteristics of material you manipulate with it. You don't need to understand how the hammer is built.