One theory is that China started trading oil for Yuan with venezuela and iran, which undermines the US Petro Dollar system. Geopolitics is too complicated. There may be other factors. Maybe there is some more information that will come out later. https://www.scmp.com/economy/china-economy/article/3346617/does-iran-have-yuan-hormuz-oil-trade-plan-why-analysts-china-are-urging-caution Observers in China have reacted cautiously to reports that Iran may allow oil tankers through the Strait of Hormuz if the trade is conducted in Chinese yuan, citing operational feasibility limits and security risks. While the plan could symbolically advance the use of the Chinese currency, its implementation would face security and feasibility challenges and could strain China-US ties, they warned.