It is much more plausible that oil will be created (oil is a molecule, not an element and so could theoretically be made by other methods).
Even nano-tech theorists do not suggest nanotechnology will be able to convert one element to another.
Asteroids are the more likely source of lots of "new" gold, not alchemy.
I only grabbed that part of the Helicopter Speech because that was when Ben made a few mentions of fiat money. But it does show how his mind works (or not.)