After visiting the entire mining area and refinery, there was hope of solving the problem of gold reserves required for the issuance of new currency.
Only by issuing new currency can the dependence of Australians on the pound be effectively reduced, and the control of the British Empire over the Australian economy be lessened.
Of course, this too is a lengthy plan. As long as the British Empire does not lose its status as the number one superpower, the pound will always be a very important currency in any region.
Arthur does not pursue completely replacing the pound in Australia, he simply hopes that the new currency can gain some circulation, reducing the British Empire's influence over Australia.
After all, now the monarch of Australia is Arthur, and for him, an Australia that is not influenced by any country truly belongs to his own territory.