But why is Iran insisting the Chinese Yuan be used? Because they're idiots?
Because Petrodollars make our global economy work, and Iran wants their partner China to be in control! If Americans lose sight of their need to maintain their role as *THE* lingua franca of international trade, then all hell is lost. The US cannot afford its military without massive consequences if it can't raise extraordinarily cheap debt through purchases of oil in US dollars immediately turned around to buy US debt to maintain that money's value.
Please do enough research to at least get the right currency before engaging in these discussions.
The forex markets are so extremely liquid and deep that trading in USD is no different than trading in any other free floating high volume currency.
Petrodollar might have mattered in 1975 when you couldn’t swap 100 million USD for 100 million euros in 2 seconds without even moving the market.