There are a few things missing I think.

I think kafka makes easy to create an event driven architecture. This is particularly useful when you have many teams. They are properly isolated from each other.

And with many teams, another problem comes, there's no guarantee that queries are gonna be properly written, then postgres' performance may be hindered.

Given this, I think using Kafka in companies with many teams can be useful, even if the data they move is not insanely big.