Not even an inch. Threat for what? For allowing people to convert their assets and make use of it simply because this technology is still not widely accepted across countries? nah.
Digital dollars are designed to be controlled by the government but thats not the case with bitcoins.
Bitcoin has its own supremacy. I dont think the digital dollar will do any harm to them.
The U.S. dollar is completely centralized. Centralization may have some impact on Bitcoin in the short term, but it cannot be affected in the long run. The more you block BTC, the more people will pay attention to BTC.
How would centralisation of a fiat currency will even affect Bitcoin? Im confused. In short term? on what sense? Cryptocurrencies and fiat such as USD has no effect with one another. They are just interchangeable if an investor would like to liquidate an amount of his asset. Even the market prices of cryptos are still based with fiat but a sudden fall on the value of one, won't result to a change with other one's market price.