Bitcoin and friends eat energy (lots of) without producing anything of collective value: there is no more creating businesses, research, jobs, products, that is, progress. A family can easily manage a mining farm that eats the same energy of a business block that normally would provide jobs for a hundred people or more; can you see the implications?

Also, since energy is turned directly into money, it then becomes money, which translates in its price being dictated by the highest bidder. Read this as: building 100 more nuclear plants per country won't solve the problem because the sudden increase in available energy will shortly be defeated by more and more of it allocated for more mining, creating in a few years a new shortage.