https://ftalphaville.ft.com/2018/01/12/2197556/crypto-fiat-coin-confusion/

A thing that can often be heard said these days is that central banks should tap blockchain technology to launch their own crypto coins.But there are many reasons why such talk is misleading and distracts from the key issues at hand.
1. In its simplest interpretation, talk of crypto fiat issuance is almost certainly a euphemism for something else: the expansion of a central bank’s digital balance sheet to every single person. Yes, really.
2. If, however, central banks really wanted to provide digital access to their balance sheets to every single person they could have done so years ago using existing technologies. Blockchain, whatever flavour it comes in, is entirely unnecessary for accomplishing this objective.
3. In general, as centralised issuers of cash liabilities, there is little need for central banks to adopt much more expensive blockchain or distributed tech technology beyond the role such technology might play in backing up their core systems. Yet, even here, there are alternatives that don’t compromise system control the way blockchain does.
4. If for some reason central banks did decide to open their balance sheets to Joe Public, they would have zero interest in doing it in a pseudonymous or anonymous manner. Physical cash transactions are drawing greater scrutiny not less, and the move is clearly towards greater traceability not anonymity. And yet, assuring privacy is the only other possible justification for using blockchain in the process.
5. Even in a scenario where digital anonymous fiat was launched to replace physical cash entirely (say to make negative interest-rate policy easier to implement), this would not go down well if the cost of the move was less traceability of illicit funds through the system.
6. All of this implies that the reason central banks have not yet extended their balance sheets to everyone universally is not due to technological limitations as much as socio-economic and structural factors.
7. Given the above, why in all the talk of crypto dollars, roubles and yens are none of the socio-economic and structural limitations ever being discussed?