In 2015, the Apple Watch will likely prompt millions of consumers to stop digging into their pockets for their cell phone and possibly ditch their wallets. Many economists are arguing that governments should consider doing something similar.

The movement for a cashless society has been gaining momentum over the past decade or so, but now it is technologically possible. Still, getting a country of 315 million people to throw away their pennies and dollars and instead embrace digital wallets would require political will and public education on a mass scale. That makes going digital unlikely in the short term in the U.S.

Too bad since there are some very good reasons to dump greenbacks and coin. Here are five:

1. It would be more efficient

As The Economist recently noted, consumers spend six hours a year looking for an ATM. The Transportation Safety Authority also reported that consumers left $531,395.22 behind in change in airport checkpoints.

2. It would help foil crime

Criminals love cash because it's very hard to trace. Eliminating this option would prompt all transactions to be recorded. It would also prevent bank robberies. As the F.B.I. points out, even in this high tech age, bank robberies accounted for $30 million in theft in 2011, a figure that doesn't include insurance fees or the 100 deaths or injuries that were related to those robberies that year. It might also put a dent in tax evasion, which has costs governments across the world as much as $3.1 trillion annually, according to one estimate.

(Of course, Silk Road showed that you can commit crimes with digital currency as well.)

Pennies are displayed at Glenview Coin & Collectibles July 6, 2006 in Glenview, Illinois. Image: Tim Boyle/Getty Images

3. It would be cheaper

In 2012, it costs double the price of a penny and a nickel, respectively, to produce each. It would be cheaper to shut down the U.S. mints and produce nothing.

4. It would allow for a negative interest rate

As The Economist explains, with physical cash, there can never be negative interest rates because consumers can always withdraw money and keep it under their mattresses. Below-zero interest rates could conceivably draw investment and boost the economy.

5. Paper money is filthy

No seriously. The stuff is teeming with bacteria related to pneumonia, food poisoning, gastric ulcers and staph infections, according to a recent study by NYU's Center for Genomics and Systems Biology.

Of course, there are many legitimate objections to this idea. Consumers should be allowed to make anonymous purchases if they wish. Not everyone has access to broadband and can afford it. An electric currency would be vulnerable to power outages, among other threats.

That hasn't stopped some countries from plowing ahead anyway. In Sweden, for instance, only 3% of transactions are made with actual cash.

As David Wolman, author of The End of Money has argued, though, keeping a certain amount of cash "on the margins" could ease the transition until a suitable digital substitute emerges that allows for the same anonymity and ease of use as cash.

Bitcoin seems to fit the bill. Maybe it will replace it as well.