Iran lets oil traded in Yuan to navigate the Strait. OPEC sets prices in Petrodollars. What is the point of staying in OPEC then? Qatar is not part of OPEC so

Iran lets oil traded in Yuan to navigate the Strait. OPEC sets prices in Petrodollars. What is the point of staying in OPEC then? Qatar is not part of OPEC so they were able to trade freely in Yuan.