When entering a credit card number into a form online to, for example, make a purchase, Safari already allowed users to quickly select credit cards stored in its Passwords & AutoFill settings. You can still do that, but in iOS 8 you’ll now also have the option to select “Scan Credit Card” and snap a picture of the card. Apple then uses optical character recognition of sorts to input the number into the text field in Safari. There’s also a way to scan and save cards using the camera directly from within the Passwords & AutoFill settings.
Another subtle, but potentially huge feature. Entering credit card numbers, especially on a phone’s small screen, remains a huge pain in the ass. Some services use this pretty basic OCR to make the process easier, but doing it at a system-wide level will be much more powerful.