Funnily enough, I know the bloke who designed the BOM weather radar page.
His advice is that it's not an official/certified source for aviation related decision making and that its use comes with a disclaimer.
The point is sometimes the BOM radar is very accurate sometimes it isn't for reasons too technical to mention. From what I've been told the BOM really do strive to deliver as accurate data to the public as is possible at the very moment that data arrives, however besides the technical challenges there are also cultural challenges with IT people who are a decade behind with their thinking and hold the place to ransom.
Caveat Emptor.