A U.S. digital currency would hinder Bitcoin’s price because the government could decide to temper enthusiasm regarding the world’s first cryptocurrency.
I don't think that analogy is ever going to work, we have seen more of those in the crypto word, we know the US government have the power to manipulate the market but it's only to an extent, if they decide to create a digital currency which they can pump in money control the price to hit the top then that's their problem, people will buy and hold the assets no argument with that, people will also make profit from it if possible, but their is one thing that they can not do, which is controlling the people, they can't force everyone not to buy Bitcoin and hold because they now own their own digital currency, they can't on their own reduce the value of Bitcoin, Bitcoinners will decided the value of their holdings not the government of any country.