It works and have always been working in an state of anarchy. And I guess you never heard of the gold standard which the USD was based upon. Trade have always been conducted via currency backed by real asset instead of fiat money until the 70's. Any currency backed by real asset would work. Matter fact, USD after being taken off the gold standard allowed the US to print money out of thin air to the detriment of many countries' economy around the world, which is why there is a real push now to create alternatives to the USD.
Stable currency is one condition, the another necessary condition is order, peace, militarily.
Both conditions are given by USA.
It can't be world commerce without it.
China talking about multipolar world, it's like a XIX century anarchist saying that state is not needed: it's false, it's just the way to replace some power by another, by themselves.
If someday USA falls, then China or another empire will occupy his position as world ruler. World commerce can't work without a superpower doing the work of police officer and banker.
USA is not ruling the world by coincidence, if his position of superpower hadn't been needed, then it had never existed. When you see big social phenomena you realize that it's not by coincidence or someone particular wish, it's due to a lot of big reasons, and when the actor disappear, another actor occupy same position and does same things.
When communist/socialist/anarchist reached power in past century, they handle power like another other regime, even anarchists, because human societies can't work without a state and a authority, the same world commerce between different states.
Here in Spain, we had anarchist ruling in Barcelona, one century ago, in Spanish civil war: they said: state is not necessary, we can work without it, but in the practice they were the authority like the worst totalitarian state, they called it in a different way, but it was the same thing.
The same is doing China now, they want USA position, but they are calling in a different manner, it's just lies, world can't work in a multipolar way. World can work with USA as sole superpower, or with China as sole superpower. We'll see it.