If you can truly abstract away an internal detail, then great. But often there are design decisions that you cannot abstract away because they affect e.g. performance in a major way. For example, I don't care whether some AWS service is written in Java or Go or C++. I do care a bit about how its indexing and retrieval works, because I need to know that to plan my query workloads.

I actually think AWS did a reasonably good job of this with DynamoDB. Most of the performance tradeoffs, indexing etc., is pretty clear if you ready enough docs without exposing a ton of unnecessary internals.