A quick precis on the Australian crown...
In 1936, King George V died. They decided that the new king's coinage should have a completely new look, and the extended period of uncertainty owing to the Edward VIII abdication fiasco gave them plenty of time to consider what changes to make to the coinage. No coins were actually issued for circulation in any of the "normal" denominations in 1937.
One thing they had decided upon was that Australia would make it's first crown - a commemorative for the coronation of the new king (whoever that might end up being). The design was largely based on the "Christmas crowns" Britain was issuing annually at the time - a large crown in the centre, with words around. Curiously, the design of the coins make no mention of the royal event they're supposed to be commemorating. Perhaps this was to give the mint "plausible deniability" in the event the coronation was cancelled or postponed.
The coins were unpopular with the general public from the start. Australians had not seen crowns in change since the time of Queen Victoria. Nor did we have the intermediate denomination of half-crown that Britain, New Zealand, South Africa and Rhodesia had. They were just too big. They soon picked up the nickname "Casey's Cartwheels" - "Casey" being Treasurer
Richard Casey, the government official responsible for authorising their issue.
They were, however, kept as souvenirs, and the handful of people in Australia you could call "coin collectors" loved them. Treasury apparently took this as a sign that the coin was popular, so authorised the issue to continue into 1938, with identical design. This somewhat destroyed the commemorative nature of the 1937 pieces.
In any event, Treasury eventually got wind of the fact that the general public loathed the things, and stopped making them. The 1937 issue has a higher mintage, and was more likely to have been "kept" as a souvenir - so the value of 1938 crowns is much higher than 1937.
The mintage figures aren't really indicative of the number of surviving specimens - as with most of our sterling silver coinage, many crowns would have been exported to the USA as scrap silver, to help pay for our defence during WWII. There were also rumours that hundreds of thousands of crowns were sold cheaply to nationalist China prior to WWII - if true, these coins would have been restruck into Sun Yat Sen dollars.
You certainly didn't see them in change after WWII. My parents (both born during the war years) never saw one until I brought mine home from the coin dealer.
Two other things to note when seeking high-grade crowns. Though ostensibly a commemorative, they were made and treated just like any other circulating coin - and fared even worse during the process, due to their large size and heavy weight. As a result, finding specimens without bag-marks and scratches can be difficult. Finally, they seem to tone very easily, with grey-to-brown toning common on most specimens I've seen. Blast-white examples are likely to have been cleaned/dipped.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis