For same process + core + hot cache & pipeline, your upper bound is something like 1,000,000x faster than a trip within the same datacenter.

This intuition is what encouraged us to run with SQLite in production back when most developers didn't think it was a good idea.

Yeah - I think that their argument would be that their approach enables you to do that, and that there are significant gains on the table without that last step.

My main critique is that it's one example, and it would be good to see the technique exercised across a number so that we can see the strengths and weaknesses.