After reading this TechCruch piece on Coin, I'm wondering if, someday, credit card companies will stop producing the plastic throw-away cards. This future would see us using our cell phones with NFC functionality or tools like Coin. That should reduce the amount of plastic added to our waste stream, and, I expect, lower costs for the credit-card industry. They won't need to manufacture, much less distribute cards.
I also hope gift cards will evolve this way. One example: I get a number of Starbucks cards as thank-yous for various efforts. The first thing I do with them is transfer the balance onto my iPhone's Starbucks app, then toss the card. Usually, the plastic card is in my possession from a few minutes to a day. It's really rather wasteful.
So, green benefits and cost savings; what a better win/win combination, right?