The China export more product to US and it benefits the China more than it benefit the US.
Are you sure? Both need each other, but as I said in recent times, what I have analyzed US needs more china then china needs the US. China has a big market that is cheap, and it doesn't solely trade with the US; many other international countries also trade with China on a very large scale. But here we are talking about the US and China, so let's talk starting within this domain. In the recent trade war, when the US implemented 125% tarrif on China, then according to some reports, chineses industuries announce to threaten by declaring the US item costs that are manufactured in China. iPhone costs only a few dollars to the company, but it sells thousands on its launch date. At the same time, China also threatened to declare some other big brands' manufacturing costs that sell in the 10k-30k range in the US. So, the US made a lot of revenue in this way, depending on China. It is not like China doesn't have any benefit in all that; indeed china also has a big benefit in it, but at this time, the US seems to be more dependent on China in my point of view.
They buy from Iran but payment are settled in dollars, this is what Iran want to break. They want to continue to sell to China purposely to get back at US, they want the oil trade be settled in Yuan so US will feel threaten by this action. A replacement of petrodollar will weaken the purchasing power US currency and I'm sure the China don't want to go down that route. As much as I don't like US and their ways of business, it will affect China if they move that way.
Yes, I agree with you here. And at this time, Iran is finding some ways to trade its oil/goods in some alternative currency, and as you said, in recent reports, they are considering the use of the Yuan and Bitcoin for international trade so that they can reduce the dominance of the US dollar in the international market. Mark my word, I believe that the US dollar will be worth nothing in the coming time due to many factors. What do you think about it?