Via Reddit:
Bitbillpay™ allows you to pay any POSTbillpay® biller online with Bitcoin. It’s instant, easy and best of all, fee-free!
This is something practical you can do with Bitcoin. I’m not sure why you’d use it over cash, but if you have some Bitcoin and want to use it instead of cash for any bill with a POSTbillpay logo on it, go nuts! There’s no extra fees either – it uses the current Coinjar exchange rate to work out an AUD to BTC value.