Absolutely this! No matter what the system is, the important part is being able to laser down to any lower levels of abstraction and reason about the specifics there. Higher level abstraction docs are summaries or getting started guides at best.
Agreed as well, though there is also the case of communicating the high level flows to others that are not software experts so that everyone has a common understanding and doesn’t have to rely on a few key developers with the knowledge. Most smart folk who aren’t developers reason pretty well about architectures so you want them to be self sufficient too.