AS a habit from childhood I’ve always carried a bit of cash. My parents were always pretty clear on the value of having enough money in the pocket to at least cover a bus fare.

So I stuck a credit card in the machine and I was sorted.

Then I walked past a Coke vending machine and was lured in by the promise of carbonated sugar and caffeine.

The machine took payWave so I tapped my card and took my Coke.

This felt like a strange transaction, so it got me thinking: Why in 2015 are we still bothering with cash?

Make no mistake, cash is enormously expensive.

The cash economy steals huge amounts of tax revenue from the rest of us that has to be made up in the taxes and charges on honest folk.

While it’s true I love a restaurant that offers a 20 per cent discount on cash payments, but I know we’re all being done down in the process.

Lugging all those paper notes from the bank (often at a steep fee if we can’t find the right branch) and back to the bank securely eats away further at our wealth.

Just counting the stuff is painful, time consuming and expensive.

Last year the Reserve Bank looked into the cost of payments and found that for sub-$20 transactions “contactless payment” (payWave etcetera) were now the same cost as cash and, for everything higher, it was cheaper to use cards.

We can transfer money from our bank accounts on our phones and the whole thing isn’t just cheaper, it’s massively more secure, and the security risks that are there we’re mostly incurring anyway.

Beyond convenience, not getting beaten up for money and tax dodgers, cash is beloved of terrorists, drug dealers and welfare cheats.

Here’s a statistic to curl your hair. Of the $60.8 billion of cash on issue in Australia as at June 2014, 45 per cent or $27 billion of it was in $100 notes.

When was the last time you saw one of those?

One suspects a lot of them are buried under patios in jam jars belonging to people who are not behaving entirely legally.

Yes, we’d need to come up with solutions to problems if we did away with cash.

Kids will lose cards (but they already lose money and at least a card can be replaced without the loss of the money) and parents will need special access to children’s accounts.

But none of the problems would be insurmountable.

There are security issues with point-of-sale terminals and cards, but we have cards and terminals already anyway.

A government that was serious about addressing revenue holes would be talking about this.

Bringing the cash economy, particularly the drug economy, in from the cold would force the payments of huge rivers of GST money.

There’s a pretty easy way to get users to stop using the existing cash, too.

For the first year let it be redeemed at banks at 100 per cent of face value, then just lop 5 per cent off its value every year thereafter.

It won’t take very long to get it all turned in after that.