It might be a fundamental flaw of Git that in order to use it, you have to understand its innards. Certainly, in order to use it effectively, and in order to avoid disaster, you need to now how it's storing data.

I've been using git for 5 years now, and I don't have a clear understanding of "its innards". I once read an overview of how it works under the hood and have a vague notion of what's going on.

What are the typical use case scenarios where you need to know implementation details to "avoid disaster"?

I can rebase/merge/push/pull/commit just fine while being ignorant of implementation.