Depending on exact specifications that is like $10k of hardware, so 4 days of rent pays the machine in full. So in this service the actual cost of the hardware

Depending on exact specifications that is like $10k of hardware, so 4 days of rent pays the machine in full. So in this service the actual cost of the hardware is a rounding error. It also needs power, cooling, a roof and some maintenance crew, but that still doesn't come close to the rental price. So what are customers actually paying for?