Just feel the quality, they reasoned: A genuine AAA rating, relatively high interest rates (although recent cuts have undermined that argument) and comparably low government debt. If trouble struck, the government still had the fiscal space to head off trouble. The argument was powerful and ultimately, irresistible.
With its safe harbour status, the Aussie dollar held up even in the face of declining commodity prices. Remember that the post-GFC low for the currency against the US dollar was 0.596.