This is a good news to all of us, because australia is not just a country, it is a continent. Imagine a land with a scale like that and has a roughly 24 million population in 2015 will accept bitcoin as a payment. The demand will increase and the price will rise. Its a sign that we will start storing more bitcoin.
Obviously, the demand will increased once Australia considered bitcoin as legal tender. Look what happened when Japan embraced bitcoin, the price is dump and reaching almost $3000 before its collapse to $2200, but it still good though. And when Australia enter by July 1, I hope we will see the same scenario. Japan and Australia are two different nation, we don't know how Australians will react to it. Of course we all hope that they will go crazy like what the Japanese did, but Australians have different cultures. So it remains to be seen.
You have to check your sources
Neither Japan accepted nor Australia is going to accept Bitcoin as legal tender. That would be a real milestone that no country has been brave enough to set so far. In Japan, Bitcoin has been made equal to other foreign currencies like the US dollar or Euro, and we don't yet know what impact that will have on Bitcoin prices long term (when the dust finally settles and hype subsides eventually). In Australia, Bitcoin will be released from the burden of double taxation, basically it is to be treated like other foreign currencies. I don't know if it is actually going to add to Bitcoin popularity there (or anywhere) since, as some Aussie said here, Australia is a "Bitcoin desert"