Earlier quoted context omitted.
That's not my reading; I believe what he is getting at (similarly brought up in Graeber's book) is that when the government controls a large enough share of the economy, the sine qua non of "money" is that you can pay taxes with it. That doesn't require anything about the historical origins of money.
I should probably read Graeber's book, though based on what I see here I might find it a bit exhausting. I hear this argument a lot in discussions about bitcoins, and I ask, but have not yet received, a good explanation. Let me ask you if you can summarize the reasoning for why paying taxes in a currency helps a currency? It seems very obvious that the opposite is true -- if you don't have to pay taxes by working in…
Unless you want to legally live and do business in a country, in which case you're going to have to pay the taxes that country levies in the legal tender currency.
The value of the US dollar, in essence, is the value of being able to live and do business in the US plus the avoided cost and risk of doing so illegally (which is generally quite high).