I think this is just Australians being Australians. It's never been a problem for me to book in various countries round the world with credit cards with billing addresses in various other countries.

One dirty little secret of the credit card industry - for many markets the billing address is not validated so you can often get away with simply giving a false address. I have used this workaround with, for example, iTunes, which isn't available in principle to people with HK Billing addresses (which all my cards currently have).