A description from the Financial Times, from someone who actually approves of it:
The monetary liabilities of the central bank are liabilities only in the legal sense. They are not liabilities in the substantive economic sense. This is clearest with currency. A UK 10 pounds note carries the inscription: I promise to pay the bearer on demand the sum of 10 pounds. That’s good to know. All it means is that I can take my scruffy old 10 pound note to the Bank of England and exchange it for a new crisp 10 pound note. If I am lucky, I might get 2 five pound notes instead. But a given face value of currency does not give me a claim on the issuer for anything other than the same amount of currency. My 10 pound note is a claim on a 1o pound note. Because it is legal tender, and because it is also de facto accepted in payment for just about anything, it is wealth – an asset – to the holder. But to the issuer, it represents no obligation to provide anything else to the holder. It is not a liability in any substantive sense.
At bottom, it is “money” that is nothing. That cannot continue.