Can you use lower dual fuel electricity rates to run a crypto miner for heating with a second back up heat source? Dual fuel electricity rates are significantly lower than standard rates.  There are devices made in Russia that are specifically sold as Bitcoin mining space heaters.  Is it permitted to use a crypto currency miner for heating and thus qualify for the lower energy rates?
Is it permitted

There are certain regions (e.g. the Pacific Ocean) where everything is permitted, and certain regions where doing stuff that are allowed by law may even land you in jail.

crypto currency miner for heating and thus qualify for the lower energy rates

Yes, this is a smart thing to do wherever it's cold and mining is permitted!
Be careful, if mining is illegal, your ISP or your energy supplier may figure out that you're mining.