Would you trust an app used to track your COVID19 status and all those you "may" have been near in the last month?
If you can't even trust the Australian COVID19 tests, this seems an ideal way to "quarantine" anybody you don't like.
Aus gov't says app is "not mandatory". I'll add, "for now."
But even if not mandatory, most Aussies are still overly trusting sheep and they will dutifully download the app. What happens when your co-worker, friend or neighbor uses the app and then reports contact with you? Doesn't really matter whether you voluntarily downloaded the app at that point, does it? Especially given the aus gov't representative said himself that a "contact" includes anyone you "may have stood in a line with at the supermarket."
Someone's making a list.
They will fail.
https://www.theguardian.com/world/2020/apr/17/australias-coronavirus-contact-tracing-app-what-we-know-so-far