During my 5 years of my startup, we had only 1 outage due to AWS because we picked us-west-2 as the primary reason. If anyone starting a company and picks us-east-1 as the primary reason, they should be fired. There's absolutely no reason to be in that region.

Why do people want to be in that region? Is it the default or something?

I know some workloads help to be colocated but all these places are connected by fiber and every cloud has a worldwide CDN it seems.