They will only allow expanding the functionality of fiat currencies within the digital environment in which we are all moving.
We already have a digital environment when it comes to moving fiat currencies and if they are adding a blockchain to that movement then it will have more transparency and the biggest problem that can cause is that the government will be able to monitor every transactions we make and will have more control over us which i am not a big fan, so i am not in favor of those kind of development that a government will have more power over its citizens.