Because it is not supported. The Marriott app is a service software about travel and travel. Registering as a member on the platform can provide users with better services and assistance. It has multiple functions so that you don’t have to worry about housing when you are playing outside. You can check your housing information online. UnionPay cannot be used with credit cards. The reason is that the software does not support and has not opened this credit card business. As of July 18, 2022, the credit cards supported by this software include visa, master, ae, jcb and other commonly used international cards.