Is it illegal to resell airline membership points?

It is illegal to resell airline membership points. According to relevant information, airlines explicitly prohibit the private sale of member mileage points for clear price tag and public trading on the Internet. Airlines have been attracting consumers through points for a long time. It is air passenger transport, and the membership points system is widely used in many fields, such as telephone recharge and credit card consumption, so as to bring new users and retain users.