>What if servers don't receive any workloads and stay cool?
Unless the service is run by madmen, that should be extremely rare; idle servers are a loss. They'd probably have a big "low-priority" queue of jobs that they sell for very cheap, in return for making few guarantees on when they'll be run. I only have a little experience of cloud computing, but Azure for example has that. It's pretty nice for things like big analysis tasks, stuff that runs for hours and you just need it done by next week.
I don't see the priority ever getting so low that you're better off cryptomining. If a datacenter got to the point where nobody is paying them better than cryptomining, I would assume that they're going bankrupt shortly.
I see other problems with this scheme, though, see above.
Biting the hand that feeds IT
