In summary, with cash, people have privacy.
The cash with us gives us privacy, but not totally, theives can later know about it and steal it, which means it does not fulfill the sole purpose of privacy, theives are the reasons banks are important. If the cash is deposited in bank, then no privacy again, while no one can keep huge amount of cash, it will be in the bank. Fiat is fiat, it brings no privacy.
With CBDCs, the government will have total control.
Privacy will totally be compromised, everything will be tracked by government, and it will be easy to freeze any account. But, this will be good to fight corrupt government officials, all their money should be in CBDC in a way all will be tracked even by the public, it will be good to fight corruption in corrupt countries.
It's really stunning how some people actually think that this is what's going to threaten Bitcoin.
It is the other way around, people like privacy, that is why they will prefer to go for bitcoin. CBDC will only just be inflationary currency just like fiat because it will be backed by fiat, but bitcoin is deflationary, another reason people will prefer bitcoin over CBDC which is not that really different from fiat, we can say CBDC has been existing before but in fiat while fiat will only be modernized into CBDC, nothing change than privacy that will be more compromised, so nothing will affect bitcoin.