This is the most ridiculous idea I have ever heard of. It was probably a project for fun within some circles, that would be all. Here's the reason. US empire like many of her predecessors taxed her subjects. However unlike any other empire in history US has been able to tax her subjects indirectly. When I say subject I do not mean US citizens living within the borders in Northern America, but I mean anyone who carries US dollar bill in his pocket, does trade with US dollar terms and especially buy US treasury bills. These subjects literally subsidize US economy doing just that. Even if US could be able to pay off its debt they would not have stopped issuing loans, why would one want to stop influx of easy money. By creating inflation of money (a.k.a. printing money) US will always be able to pay her debt with lesser value. Same amount but less value.