There is nothing unique or special about CBDCs. It is just like a checking account at the central bank. You are just shifting the liability from commercial banks (Barclay's or whatever) to Bank of England. There is no risk difference since commercial banks have state guaranteed deposit insurance anyways.

It won't change anything unless you add money for people to use. But given that Labour has "sound finance" brainworms that's unlikely.

Fiat currencies are not failing. These cryptobros see decline of the Dollar and rise of BRICS etc and go "its end of fiat currency". Yuan, ruble, rupee, rand and real are all fiat currencies. The "replacement" for dollar is not bitcoin but other fiat currencies.