It doesn't make much sense to ban Bitcoin, with its current level of adoption its not a threat to the established financial system, so the government would have to waste resources on enforcing the ban (more work for officials, law enforcement, etc.) and achieve what - nothing? Plus they will be killing some legitimate businesses that could be paying taxes, creating jobs, etc. - even if its small compared to the whole economy.
Exactly, it would be correct to say that the USA does not consider BTC a threat at this time, whether for financial or national security. Those who followed what was happening in the USA when it came to Libra, could hear what some politicians think about BTC. Congressman Brad Sherman is a great opponent of crypto, and calls for complete ban - but at the same time, he is saying that BTC is just a small baby (compared to Libra project).
Today everything is viewed through money, and let's be honest and admit that the current market cap of all BTC is just $154 billion, and the USA budget for 2020 is
$4,746 trillion. Of course, $154 billion looks like pocket money when compared to all that trillions of dollars.
In fact, it would not be difficult to ban BTC - first declare it illegal, then ban all crypto-exchanges and remove all crypto ATMs. Declare it terrorists and criminals money, and accordingly punish anyone who is caught using and possessing it under existing laws.