Why is the "dirham" currency popular in foreign trade? International Affairs Expert: Some local Chinese companies originally have an Iranian owner, and the cost they receive inside China will include added value and side costs. Therefore, it is better to use "yuan" of foreign origin than local yuan. The statement that even Chinese businessmen prefer "dram" is not very technical. The reason why the dirham currency is popular is that it has more suppliers, it is not a sanctioned currency and it is readily available.