Simply they will going to be left behind if they will allow that to happen something like we never expect that US will be that to strict with the regulations about crypto but sooner or later they might accept it or not they will have no other choice when futures comes in the market like in china as pf many people there are already using e payments systems more than their cash or fiat.
There is nothing simple about America. America was the country that won the second world war and as a barometer of the world economy when the dollar was made a global currency.
America is a country that has a wait and see attitude towards cryptocurrency. Although many countries have adopted and legalized bitcoin, the United States has a skeptical view of bitcoin. Today the world sees America as anti-cryptocurrency because of the view of Trump as the country's leader who is a barometer of the world economy.
If we investigate further, the IMF which is identical as a tool of American interference in other countries with its debt instruments has signaled approval that the central bank should issue fiat-based digital currencies.
https://www.imf.org/en/News/Articles/2018/11/13/sp111418-winds-of-change-the-case-for-new-digital-currencyBlockchain technology can provide a serious impetus for the transition to a new lifestyle. A society without cash is no longer a Utopian dream and because each country faces unique circumstances surrounding the use of cash and the adoption of e-money. Cryptocurrency can offer a real alternative to other forms of payment, but it is not wise for central banks to offer fully anonymous digital currencies because they will potentially create a safe space for criminals. Digital currencies supported by central banks can help promote financial inclusion, security and privacy in payment systems as a cheaper and more efficient alternative to cash. USD-based stable coins are the safest way to follow the flow of digital economic and financial technology without threatening the interests of the United States.