> free up resources (...) while they install new hardware That's likely not the reason. It's more likely caused by inherent spike-y ness of the traffic, given

> free up resources (...) while they install new hardware That's likely not the reason. It's more likely caused by inherent spike-y ness of the traffic, given that most GPU instances are probably used for batch numerical computations (like training neural networks). The pricing incentivizes using a lot of nodes for a shorter amount of time, much like in the SHA example.