There was a time, way back, when credit cards weren't processed electronically by stores. Instead, the card was placed on a little mechanical contraption with a receipt made from carbon paper sandwiched between the card and a slider thing. The slide was then pushed across the card, which put pressure on the carbon paper and the raised digits on the credit card – copying down your name, credit card number, and expiration date onto the credit card receipt.
But when was the last time you saw such a device?
I can't see any other reason for the characters on a credit card to be raised the way they are, and if these antiquated "card readers" are the only reason for it, maybe it's time to look into eliminating it.
Is there any reason why this information can't just be printed onto the card? Any reason why a perfectly flat card with numbers that can't wear off doesn't make sense?