Yes, there are certain meals that require a credit card in order to reserve your place, namely, Cinderalla's Royal Table. It is very popular and they can't have people booking and not showing up. That is precious table space that can be used for another family. Make certain, if you have given a credit card to reserve an ADR that you show up or cancel in good time in order to avoid the charge.
Yeah - the Princess dinner in Norway is the same way! I cancelled all of the ressies that I don't want (except for the duplicate princess dinner - still not sure which day we're doing Epcot! Only problem, princess dinner is 2 day cancellation notice while all the others are 1 day). I have 2 ressies at Cinderella's table for breakfast - the first day of the trip and the last day of the trip. It's my daughter's favorite.