For one it's a lot cheaper - I use Hetzner Cloud and I have plenty of resources for just 70e/mo. But I also like devops etc so I don't mind it :)
Later of course I can switch easily to a managed service if needed.
I dunno. What makes me wonder is, if Hetzner Cloud can offer an excellent service (great performance, very reliable, very good control panel etc) for those prices, try and imagine how much money AWS/GCP/Azure make!!