I've been building a little hobby-ish project recently to serve a gaming community I'm in (Splatoon) and I've been using fly.io for it. Being able to run it in multiple regions is useful for this in my opinion because the Splatoon community isn't just concentrated in one place, it's all over. If I hosted in the US then players from Japan would suffer and vice versa.
Even if this little project doesn't go anywhere, I still see it as a (probably) rather useful experience for someday when I'm like, out of school and stuff.
It's really neat to learn about I think. Right now I have it running in the Eastern US, Amsterdam, and Tokyo for about $10/month.
... except "once it scales", you realise that you're paying through the nose for cloud services "because growth", so you end up looking at on-prem again, and finally decide it's better value?
Sell spades during a gold rush.