Last month when I flew out of TPE, I got stopped AT THE GATE and being asked to show my credit card by the agent who scanned my boarding pass. I only got hand luggage and had mobile boarding pass. Usually they would ask my passport to verify my identity (which they obviously should given the incident of a lady who flew with CX on a HX tix in Feb). I was stunned nonetheless I showed her. Then I asked the agent is it a new procedure in place as this is my first time ever encountering this. The supervisor standing nearby heard my question and quickly came and told the agent (who is quite new) that no need to check credit card on DM.

So to cut it short, they still check credit cards but I think black and white policy is that not on DM.