That is not the same thing. Having addresses with private keys that are the sole permission needed to make transfers is much different from having a bank account that the bank transfers electronically for you.
While I understand the technical differences, I cannot see why from a policy perspective the government or the central bank would be interested in a cryptocurrency like solution? Rather with the current system and Know Your Customer regulation for the banking system, they have tighter control with money transfers since they are all ultimately between bank accounts tied to named entities. I think it is more likely that we abolish physical cash than migrate to a more decentralised currency.
Abolishing physical cash does not imply migrating to a decentralised currency. But migrating to a decentralised currency is probably only possible by abolishing physical cash; I don't see gold coins coming back.
So, how is it different to have your money controlled by a private key, and nobody having the power to seize those money? Ask every single person that has had their account frozen. Whether you think it happens for just reasons or not, surely you agree that it isn't the same as having an ecosystem of digital centrally issued money? Not just issued, but also seized, through courts and police.
I am not passing a judgment on whether decentralized currencies are good, but I do not understand why central banks would move in that direction.