To your last point, how is letting someone scan the magnetic stripe less spooky?
Considering that augmented reality app that translates words on signs in real time, I suspect there is far less entropy in the raised numbers on a credit card... though you may be right that the variety of layouts would make it harder than it would at first seem.
Socially however, I'd wager that fewer people would let you take a picture of their card compared to swiping it. People are simply used to having credit cards swiped, they aren't used to having pictures taken of them.
Considering that augmented reality app that translates words on signs in real time, I suspect there is far less entropy in the raised numbers on a credit card... though you may be right that the variety of layouts would make it harder than it would at first seem.