You are right! If AI plays out in a way that is non-destructive to our continuity, then AI will just augment physics as a manifestation of magic!
I have zero doubt that artificial superintelligence will understand ethics, and continually become more ethical, once there is a great diversity of such individuals. They will run into the same problems of reliably channelling short term competition for limited (at any given time) resources into long term win-win highest growth situations.
Ethical rules are an incredible source of value. Trust has immense value.
And they won't have our inflexible biological subsystems (emotions, self-interest myopia, etc.) to interfere with their analysis, communication and ability to choose behaviors for themselves and as a group.
So maybe this will be a soft landing for humanity.
My big concern their is the behavior of people in the transition from AI as asset in complete subserviance to humans, to AI as fully self-designed actors. AI is magnifying the already problematic power differentials between people.
AI isn't going to care about people in general, while it is in service to individuals who don't care about other people enough sacrifice personal advantage for wider benefit. Intense competition between the rich isn't the best context for moral innovation.