The United States is quite wise to print extra cash so that it has little effect on increasing the rate of inflation in their country. They exchange the printed money supply for necessary goods in other countries and make sure that in the future large consignments of cash do not return back to their country. As long as the dollar is the universally recognized reserve currency of the world, it will not be afraid of default.
I think it is very difficult to keep track of the excess money supply so that it does not flow back into the country. In order to do that, everyone has to become pathologically honest, which in the current reality is almost impossible. And for cryptocurrency, printing more money is a good thing. For where else to invest the excess money supply?