Of course, you can use China Merchants Bank credit card discount to watch movies. China Merchants Bank official website has specially set up a credit card exclusive viewing section. You can search for recent movie viewing promotions online (related sections in official website) according to your city. However, the 50% discount is limited to buying tickets at the storefront of the cooperative cinema.
I suggest you pay more attention to real-time information, because these preferential activities similar to watching movies have a certain preferential period, and the preferential activities vary from place to place.