In fact, the United States has been doing this for decades. The reason is that the dollar is now a hard currency (though not so hard), that is, an international currency. Dollars printed by the US government can be directly used to buy things around the world. The main example is that the United Arab Emirates only sells oil in dollars. So the U.S. government can directly print dollars to buy oil. The China government needs to convert RMB into US dollars to buy oil. Because the United States is the world currency here, as you said, the currency circulation and commodity value should be equal, so the economic growth of emerging countries such as BRIC countries will increase the world commodity value, so the US printing dollars (increasing the global currency circulation) will not lead to serious global inflation in a certain period of time. Because the purchasing power of the dollar is all over the world, it will not lead to inflation in the United States. However, RMB can't work, because the purchasing power of RMB is at home, and it needs to be converted into dollars when going abroad. Therefore, printing more RMB will lead to domestic inflation and disrupt the economy.

So if you print more RMB to buy dollars, but there are too many RMB, will it involve whether others are willing to exchange dollars with you? This involves the issue of national strength. Unless you have a strong national strength and your Jianghu status is recognized by everyone, you can't buy dollars if you trust your currency. But then again, when our Jianghu status is recognized by everyone, we don't need to change dollars, just buy it in RMB.

This is why most countries in the world are export-oriented economies and want to export. Because if you don't export, you can't get foreign exchange, and unless there is nothing outside, you can't buy what you need. If you want to buy something, you have no foreign exchange, so you can only borrow money. But international relations are not good. Maybe others won't lend it to you yet.