Australia did adopt the Pound. The Pound was used until 1966 when Australia swapped over to Decimal Currency.

Here's an ad explaining to Australians what swapping to Decimal Currency (the Dollar) would mean. One of the reasons given was that Decimal Currency was easier to work with since adding it up was rather straight forward and thus there would be fewer mistakes.

https://www.youtube.com/watch?v=5ZTeWLA1LAs

Australia had adopted the Australian Pound in 1910 (9 years after Federation during which time it was using the Pound Sterling) so that means that Australia used the Pound for longer than it has currently used the Dollar.