They won't get around to it, because stopping the mining of all cryptocurrencies that sci-hub could use to pay for uptime is more work than stopping sci-hub.

Since stopping cryptocurrencies is harder than freezing third party payments (evidence: see Wikileaks), this is a single, narrow example of the usefulness of cryptocurrencies. Researchers get the convenience of sci-hub's frontend for longer than they would if sci-hub had relied on a third party payment system.