The "regular" distro installation process with Hetzner is a pain in the ass. They have a limited number of [https://en.wikipedia.org/wiki/Rackmount_KVM KVM devices] and
loading custom ISO images through that KVM interface is terribly unreliable. Alternatively, you could provide connection details for a SAMBA server and load an ISO that way but this is still too much trouble
Thankfully, they have a much simpler process for setting things up.