Why do we have a Queen?

Answer

Australia has a Queen, which, under the Australian Constitution is always the monarch of the United Kingdom, because Australia is a constitutional monarchy. We should not forget that the Australian Constitution was drafted by Australians and, furthermore, in the referendums prior to Federation in 1901, the Australian electorate voted to be a monarchy and this was confirmed by the Australian electorate in the referendum of 1999.

The Queen is always represented in Australia by an Australian as Governor-General.