10% service charge is standard on all hotels in Taiwan. You do not get Marriott points on the service charge or tax (another 5%, again usually included in the room rate).

The hotel's local website can advertise a price that is different from the price on Marriott's website, and they can exclude Marriott points/benefits from those bookings. This is not covered by Marriott's best rate guarantee, which only applies to third-party bookings (with a bunch of exceptions).