For now. I know that my iPhone 5s will allow me to manage Pay for use with my Watch, however, Apple has not enabled that functionality within the Passport app on my 5s yet. Now what hardware does a 5s have that allows me to manage Pay, that a current MacBook doesn't? Or an iPad for that matter? If iCloud allows me to delete a credit card, I don't really see why I couldn't also add a credit card as well, other than Apple hasn't enabled that particular functionality.