Time to kill cash

In the most recent copy of Wired, there is an interesting op-ed about the costs of cash, that is, hard currency.  

The US government spends almost one billion dollars per year on currency, and over half of that is to make coins, which are utterly useless.  I agree with the author that it is time to end paper currency, at least in the US where everyone from McDonald's on up accepts at least the three most major credit cards.  For smaller purchases (for example, a garage sale) the technology is already here to "flash" a small payment via your smart phone's bluetooth.  And if one party of the transaction doesn't have that, there's always PayPal.  

Not only would we save a billion dollars in taxpayer money, but we'd save all the costs involved in shipping and sorting the paper money and coins.

There are some who argue that food workers will get hosed because of the lack of tips, but credit cards support tips.  I think the real opposition is from those who don't report their tips, but they are committing tax fraud anyway.