Thanks Ananda. Such arcane mysteries are well outside my limited understandings.
No worries Ngati..I've been working with financial Industry more than two decades. Even then I still couldn't understand all the mechanism. It's a mechanism that 'supposedly' should be simple but in reality getting much more complex to make the '1%' of the world getting richer, while the rest of us as the world 'middle class' has to work hard just to meet ends need.
However it's still the acceptance compared to other alternative on trading.
Between pollies and cybercrime, perhaps we will all be back to barter transactions.
John, I will try to give simple ilustration on why direct barters between two trading nation will be more expensive compared to using current international market trade mechanism.
Let's put Indonesia and Australia, as direct neighbor they should can trade with each other without the need of Global market right ? Well in the reality they can't..they need to arbitrage their exchange rate to International Money Market mechanism.
1 AUD is IDR 9,600..where that valuation coming from..well simply said because 1 USD is 1.47 AUD, thus make 1 USD is IDR 14,100 (give at take several basis point adjustments).
In short, every other currencies arbitrage their valuation to each other based on their each valuation to USD.
In theory the global money market valued by a bucket of dominance currency like USD, Euro, GBP, Yuan, and Yen..as the currency of leading trading nation's. However USD is the only currency that trading nation's used as arbitrage on trading with each other even when they don't have to trade with US or US system. Yuan used mostly on trading with China, Euro used mostly on trading with EU, but USD can be used when trading with everyone not just the US.
If we back to case of Iran, that INSTEX system that French initiate basically can be say as close to barter system in modern world. Because of US sanction, Iranian currency can't be traded to USD or USD influence mechanism. However if the Iranian Rial can't be traded on global money market, then how the Euro's will accept the exchange rate ?..how to determine the exchange rate ?
The answer again has to set up separate mechanism, and it's going to cost Iran more cause the volume of trading will be limited. The Euro's will not accept Iran Rial cause it's worthless in Global Market..thus how to value Iran's Oil..what Euro value that Iran can accept ? Well the answer is kind of barter that will discount Iran price, cause limited exchange mechanism that available to Iran at this moment.
Iran oil to China has to used only Chinese trading with Chinese medium, since no other method available. Same thing with EU, they have to go this INSTEX since no other mechanism can be available between Iran and EU to trade.
China try to used Yuan on International trade, however in reality so far only less then 10% of Chinese global trade that using Yuan direct bilateral exchange regime, the rest still valued in USD. If a second trading nation in the world still has to used USD, you can imagine how difficulty of a small trading nation like Iran has to face if they can't used USD on International trade.
USD is the only currency in the world until now that valued not entirely of it's origin country (US) condition, but also how much everyone else still using it as medium of exchange in International Trade. While every other currencies mostly determined by the economic condition of the origin country it self.