If you mean specifically flyio.net and not just fly.io the company, I'm guessing they host their status page on a separate domain in case of DNS/registrar issues with their primary domain.

IIRC their value prop is that they let you rapidly spin up deployments/machines in regions that are closest to your users, the idea being that it will be lower latency and thus better UX.

It’s basically what Heroku used to be but with CDN-like presence.

Hosting service that has a lot of interesting distributed features.