Central bank digital currencies differ from existing digital money available to the general public, such as the balance in a bank account, because they would be a direct liability of the Federal Reserve, not a commercial bank.
As far as the public is concerned, the only change will be faster transaction processing and new capabilities being offered by your bank --- such as transferring funds to friends/family from your banking web site/app in real time while sitting at the dinner table.
All purchases will continue to be made in good ole US dollars and all accounts will remain with your commercial bank of choice and subject to existing laws.
Basically, this will facilitate interbank transfers in order to provide a much needed update to the aging and slow ACH system which was designed for the paper check era. No banks will be killed in the creation of a CBDC.