Their pricing seems to rely on customers that don't maximize power consumption and hardware wear all the time, and I can fully understand if they ban specific use-cases like this from their hardware.
Long term vs. short term thinking. It's more beneficial for them to maintain long term customers than mine a volatile cryptocurrency in the short term.
This does not logically follow. Why does Nvidia bother to sell hardware then when they can just keep the most powerful cards for themselves and use them for mining?
If you rent out your servers at a fixed price and they can mine crypto on them for a profit, then there is a high chance that your flat-rate pricing is not high enough. They would need to consider their missed earnings from not mining themselves as an opportunity cost of renting out servers instead.