A cloud provider's business model is more-or-less selling CPU cycles to customers, in a variety of flavours.
Regardless of their opinion as to "think cryptocurrency is a scam" they can make money selling CPU cycles to people who have bought into the cryptocurrency thing. Bonus if the cloud provider can offer "managed blockchain" flavour rather than "here's some vanilla infrastructure, you can run your blockchain stuff on that, just as well as you can on your laptop."
It's the old "Selling pickaxes during a gold rush" plan. You don't actually have to worry so much as to if there's really gold to be found. Just if the miners buying pickaxes think that there is.