80ms is the network latency not response times. That's the number fly.io can change and realistic best case is going from 10-15ish ms staying within a city vs 80ms going to a server on the other side of the US.
I'm just saying, if your application is already fast for your users --- anything in the ballpark of 80ms is fast enough --- geographically distributing it might not make a big difference. I'm agreeing with the comment (or at least, its subtext).
If all of your users are in the US you won't gain much from geographical distribution. Where this gets really interesting is when you have users all around the world.
