I can think of at least two potential downsides Fear of losing control in future. For example Ethereum presently seems to be quite secure based on the potentia

I can think of at least two potential downsides Fear of losing control in future. For example Ethereum presently seems to be quite secure based on the potential reward of an attack vs the assets that might be deployed to attack Ethereum. But if a Fed-backed stablecoin relies on Ethereum, then a very expensive attack on Ethereum could become more attractive to an adversary. And how about the risk of an accidental coding error by Ethereum developers in a future update? Fear of lending legitimacy to other cryptocurrencies and tokens. Their values would explode if the Fed issued an ERC-20 token on the Ethereum blockchain