I think part of the rarity and value is because it's a 240 volt unit with the Australian plug. I can't say there would have been that many sold when it was new compared to US or Europe. Means that the end user doesn't have to use a power adaptor or anything like that.
Then again it could be because Aussie power plugs have 3 pins instead of 2 and that's why it's soooo expensive!