Bank of England's Chief Economist suggests ditching cash for cryptocurrency
finextra.com
finextra.com
At present, the bank can choose not print more money (leading to deflation), or print money to slowly increase the amount of money in circulation (leading to controlled inflation, reducing the value of money in private wallets and encouraging spending behavior).
Digital currency will allow the state to simply dirrctly reduce the value of money (negative interest) across all private wallets to encourage spending behavior.
It is a very interesting approach that I think challenges our intuitions about currency, and will take some time to get used to.