The pay thing reminds me of a recent experience on Aeroflot. I wanted a beer and flashed them my VISA card (alcohol on Aeroflot is generally buy on board), but they declined that. They went on with the trolley while I sat digging my roubles. Of course I want to pay for things. The FA then came back after the service to collect garbage etc and I lended her the payment which was 82 roubles. She was confused and asked if I wanted another one. I explained that I did not pay for this and I just wanted to pay. Could have a free beer I realized, but I am a honest passenger. I think every airline should take VISA and Mastercard. In the Untied States it is creditcard ONLY most of the time.