As long as you have to pay your tax in the currency of the government, the currency of the government will continue to be the money - everything else will merely be another commodity - exactly as we have it today.
Money is the economic good most desired in a market place.
In today's market, there is one, and only one desire that touches almost every man woman and child that is directed universally - taxation.
That which solves paying taxes will be desired by everyone - and that is the US$.
If a whole basket of currencies or commodities was dumped by God above into the market over night - repealing the tender laws - over night, only one would remain to be seen as money, and that is the US$.