This looks suspiciously like a banking cartel. Remember, the purpose of banning cash and moving to a digital currency is to eliminate anonymity in your private financial affairs.
It’s also possible central banks could phase in a digital currency (complete with an account at the central bank) alongside of paper money. But you’d have an incentive to convert to digital, ie you might earn a bigger interest rate with an account at the central bank.
Whether this new digital legal tender is linked to gold or backed by something other than reserve assets like government bonds will be interested. A gold-backed, government-issued digital currency might take the wind out of the sails of Bitcoin or other crypto-currencies.
Of course a central bank issued digital currency is precisely the opposite. It’s centralized, not decentralized. And it’s designed to make your monetary affairs completely transparent to the financial authorities. They way to tag, track, and tax everything you do.