What is that use case though? The page says that they only host regular Pis and optionally a USB SSD. So they can't do anything that a regular cloud server can't do - no custom hats, etc.
I have a Pi 4 home server, and the biggest issue right now is that my home upload is a bit weak for remote video streaming. So this product could interest me, in theory - saves me from having to migrate all my data & configuration to a cloud server. But I would rather pay Hetzner a very similar amount of money to get a VPS that's about as powerful as a Pi (probably more) and still have the physical Pi here at home as a fallback.
Maybe there are ARM-specialized, highly distributed tasks for which a fleet of Pis is particularly efficient?