The British Empire hardly needs an introduction. While the British Empire is indeed mighty, its imperial title deriving from India decided that it's not deemed a legitimate empire in the eyes of the European royal families.
This is also why King George V was quite envious of Arthur. Even though the country he ruled was more powerful than Australasia, it was Arthur who became Emperor.
Moreover, the European royal families virtually had no objections to Arthur's ascension to Emperor, but his claim to the Indian throne was at best, self-amusement.
If King George V were to proclaim himself as Emperor George, he would likely be greeted with nothing but mockery from the European royal families.
On the second day after the establishment of the empire, which was January 11th, 1933, the Australasian Imperial Government announced a significant piece of news: