It's fairly difficult to find actual details on ACUs and how it all works, the best I found after spending significant time looking was things like: https://www.jeremydaly.com/aurora-serverless-the-good-the-ba...

According to AWS you're paying for chunks of CPU and memory on a per second basis: https://aws.amazon.com/rds/aurora/faqs/

It's hard to imagine that the CPU capacity is measured in anything other than CPU cycles (time slices of physical capacity) — in the same way it's hard to imagine that the memory capacity is measured in anything but bytes. But whatever, I don't care. It's cool, good for them. The point was... you don't think you're paying for reads of records that are cached? I give up, I fail to see how this can really be a good faith discussion.

I don't know how all other serverless database offerings do pricing. What difference does it make? They're all different. As a user, you want it to be based on your usage and to be fairly and reasonably priced while also being easily audited and predictable. Those are the key properties I would care about.

I honestly cannot see how you could be missing the point by this much and still be operating in good faith so I'll for real, for real stop. :-)