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.