No, it’s not some golden/platinum credit card. It’s the German Bahncard (a card for discounts on German trains).

It actually opens the door to access ATMs after the working hours of banks. Really strange, but I could really use it to open the door at the Sparkasse close to Johanniskirche in SB. I was just absent-minded again and took out the wrong card. When I was about to put it into the ATM I realized that it was my Bahncard. Apparently, any magnetic strip will do.

Next time I should try to see if I can also withdraw money with it.