eh. It's something that made sense over ten years ago. Very little content was hosted locally within Australia so most traffic had to go over the expensive links to other countries (which are obviously constrained in bandwidth). Privileged/unmetered content was often things like local Steam mirrors or whatnot which was closer to the user/ISP.

Now that more and more content is cached locally, there's less and less of a need for it both bandwidth caps and privileged content.