Centralized ecurrencies have a terrifying implication that outweighs other concerns imho.
Consider - we have become used to centralized paper currencies and the abuses that go with them, such as centralized authorities arbitrarily raising or lowering the value of everyone's net worth by manipulating the money supply or interest or exchange rates.
However, with centralized ecurrency, such authorities can arbitrarily target small groups or individuals, rather than "everyone at once". For example, you might discover one day that your "ecurrency access privilege" has been revoked - your authorization card - your unique personal identifier - just won't work all of a sudden. In a centralized ecurrency world "they" can pull the plug on you any time and instantly make it impossible for you to buy or sell anything at all - you would become what was called a non-person in the Soviet era.
Think of the horror stories posted from time to time on this forum by people who have had a bank account closed suddenly "for no reason" or "because they used
BTC". In a centralized ecurrency world, one could not just open up a new account at the bank across the street.
Hey, it will save trees, and everyone knows paper money carries germs, and and.... all true - it's a matter of balance, and "the authorities" have their own view of what balance is appropriate. Paper money is an abomination (unless you control its supply, in which case you might think it's pretty cool) - centralized ecurrency is worse, far worse.
For me, this control issue is a bigger concern than privacy issues involving centralized ecurrency, which are themselves huge.
Bleak prospects. Decentralized crypto is an idea whose time has come but - interesting times ahead before it becomes the norm. Stay alert!