Well, I didn't have opportunity to use this card. I wanted to visit exclusive waiting area in DUS, but it was to far from our gate. Our luggage was not large enough to force to use the card. Finally, there were no queues to check-ins, so there was no need to show the card neither.
Today we're flying back from CUN, but in J, so we'll have premium services on other basis.
Best regards, Bartek