It's not like you can't trade dollars already.
Source for that claim? Because it sounds like you just pulled it out of thin air.
Most every “common” person I know with any Bitcoin is using it as a get rich quick scheme and very much do not have other financial investments to offset potential losses. I’ve begged one buddy to hedge his bets because I expect like others here he’s going to lose his ass at some point.
https://www.federalreserve.gov/faqs/what-is-a-central-bank-d...
For smaller banks if you assume that an alt coin would continue the goals of the FedNow instant payment system that's currently in the works would cut out the banks that currently operate as a payment intermediary [1, "The structural bank disintermediation issue" ] and seems like it could indicate a shift away from fractional reserve money, where the bank could for example hold $2.5 and create $100 in loans, which then increases the power of the central bank.
I think in such a scenario people stand to potentially lose out due to a increase in state power that would result.
[1]https://www.ecb.europa.eu/pub/pdf/scpwps/ecb.wp2351~c8c18bbd...
There are plenty of other countries that peg their currency to the dollar, by the way. That is very different from making your currency digital-only.
Some here would present these ideas as positive, but I'd argue that "common people" would be the losers in this scenario.
Depending on how much tinfoil is in your hat, central bank digital currencies open the door to surveillance and control. Consider the elimination of physical cash and the implementation of a social credit system that sees exactly what you buy, and from who. I don't think the US will get that far, especially not soon, but also think having cash as an option is fine.
China has moved faster with the digital yuan; there are discussions over things like whether there will be capability for anonymous small transactions, or just private transactions, still viewable by the government, just not by the other party.
I'm not versed in the space but also heard payment processors and especially banks are against CBDCs, since they would get cut out of various transactions and even loans.
There are proposals to use consumer's electronic trail to create "alternative credit scores". CBDCs will allow this. The WEF proposal includes AI/big data hype, psychometrics, social media use, contacts and purchase history.
Social media and smart devices have also been proposed for use as part of gun control schemes in the US. Some called this a "social credit score".
https://yro.slashdot.org/story/19/08/30/2037251/the-plan-to-...
A digital dollar would be spent on actual goods and services, and would leave crypto coins in an "emperor with no clothes" situation.