It would also be pretty handy for tourists to be able to have a Suica ready to use as soon as they step off the plane. Load from iTunes account before departure, skip the (often quite busy) JR ticket office at the airports, tap to board or head to a machine to pay the express train fee.
I'm also hoping for tap to pay to work with Japanese CC issuers, if only because I've got a prepaid Visa from Credit Saison (some drugstore chain there issues combination prepaid Visa/point cards, no ID required, works great for iTunes and NicoVideo) that has a stray couple hundred yen on it that I'd like to use before expiry.