One of those things being “store it in a relational model” or “write a sum to a key value store” or something else.
This ability comes for free with Kafka, but is very not-free when using a relational model.
It's not missing that because it doesn't even address that. I'm answering a specific point.
> Relational database seem to be a crazily overengineered solution in search of a problem
Why would an answer to that need to mention Kafka consumers?
This is the part I was responding to.