People accept dollars because they believe that money is still backed by gold (as it was until the end of Bretton Woods), or because (unfortunately) they believe the government will guarantee the value of the currency.
This part is very true, currently people are deceived by such a statement, in fact, according to some books, such as that of Master Robert Kiyosaki, he suggests that saving in FIAT money is not recommended, recommends that money should be moved in terms of investment, real estate investment and now resonates a lot in people investing in gold and especially in Bitcoin.
Since bitcoin for many is seen as a refuge of value, especially for countries with high inflation, it is notable that it is the best way out in terms of survival and operations that can be performed more easily and quickly. Banknote printing causes inflation, comparing it to the deflationary economy that Bitcoin offers is really a plus.