Do you mean the "ISP-only" DNS restrictions of 2016? That was just a lame attempt to appease the film and media companies. Unfortunately for Aus Gov, DNS registries are not solely operated by Australia.
What's particularly strange to me is that devices such as Google WiFi come preconfigured to point at Google's DNS, so a layman in Australia will be bypassing these blocks without deliberately doing so.
It did have some interesting effects though. I know of several of my old school acquaintances who were very technologically challenged that managed to navigate their network settings far enough to change DNS.