Amex Plat comes with mid level status at some hotel chains (SL Golden Circle Jade possibly being the most valuable as it can status match to KrisFlyer Gold) and the ability to book hotels through the Amex Fine Hotels and Resorts programme, which is quite useful for the benefits it provides. That being said, those benefits are certainly not worth the HKD 7,800 annual fee. If you hold residency status elsewhere it may be worth applying for the Amex Plat Charge there.