I was one of the "21 experts" in the FocusEconomics article "21 experts tell us what the future looks like for cryptocurrencies and blockchain." My bit reads as follows:
Governments will retain control of currencies. But the blockchain technology is very exciting. What is most exciting is the possibility that the credit-card/debit card oligopoly might be disrupted so that fees come way, way down.
Many central banks are working toward issuing their own digital currencies. The simplest way is to give fintech entrepreneurs low-cost access to a central bank clearing mechanism with streamlined regulations for fintech accounts that are 100% backed by central bank reserves. Some central banks are thinking of giving individuals the equivalent of a central bank reserve account.
There are two big effects on the world economy and financial markets. The first is that a 1 percentage point reduction in credit card/debit card fees from disruptive digital competition is like a 1 percentage point reduction in distortionary taxes. The second big effect on the world economy and financial markets is that when a bigger and bigger fraction of transactions are electronic, central banks will see a smaller political cost to modifications in paper currency policy that allow deep negative interest rates. See "How and Why to Eliminate the Zero Lower Bound: A Reader’s Guide" for a discussion of possible changes in paper currency policy that keep paper currency in the picture but allow deep negative interest rates.
We can see what the other experts say in the article.