foxie48
Venezuela sells it's oil to China, India and Russia at a discount and they usually pay in gold or some other non dollar way. There is a strong but complex link between oil prices, the petrodollar and the US economy, so part of this move by Trump is probably about forcing Venezuela to sell oil in petrodollars. Selling for gold weakens demand for the U.S. dollar and undermine its status as the global reserve currency which in turn affects it's borrowing capacity. Sorry this is the best way to describe it!
The supplier could sell in whatever means requested, gold, dollars, arms, wheat or anything else but it’s all got to relate to the reserve currency.
Being the reserve currency gives the dollar a lot of advantages, sellers trust it more than anything else, unless there is a need to avoid any sanctions against banks. This is where gold comes in it holds its value and is untraceable but vulnerable to theft.
Many countries have very weak currencies so commercial transactions are done in US Dollars even tourist activities, hotels etc you pay in $. Oil is just part of the global trade, most commodities including food are priced in $.
The US dollar is not immune to variation but until there is a more stable currency it’s the best we have got, honestly I don’t see that changing