Why would I care? I have <30 ms ping to AWS. Maybe there's an argument for this for something like realtime-ish like games, but this feel likes a massive premature optimization for anything solving typical business problems.

That's not meant to be a snarky question, I genuinely don't understand what business problem that's going to be solved by saving at most 30 ms. Anything written in Rails/Django, talking to a DB, etc. is going to have request latency dominated by other parts of the stack.