On one hand you have QLD/SA/WA which are probably the places least effected in the world by COVID. QLD for example with a population of 5.2 million has had a total of 7 deaths from COVID over the entirety of the pandemic. Schools, shops and workplaces have all been pretty much running as normal the last 18 months in these states.
On the other hand you have the South East states which have large active delta outbreaks and have gone through long lockdowns, especially Victoria. These states have given up eliminating COVID and are planning on letting COVID spread as vaccination rates meet targets.
Residents from the SE states are effectively locked out from the rest of Australia. State borders are shut and have been on and off for much of the pandemic. Thus Australia is in some ways operating as two countries at this stage.
What’s more international travel to Australia is effectively shutoff. The only people allowed back are Australians and there is a wait list and you better be planning on moving back to live permanently.
Obviously no one wants to split the country in half. No one wants suspend international travel indefinitely. In particular the federal government views its reelection chances as effectively riding on getting things to a semblance of normality by Christmas.
Yet residents of places like SA and WA obviously do not want to give up their COVID free status.
Hence you see the search for solutions like this. The app does address a genuine problem. In particular, hotel quarantine was introduced in Australia after home quarantine failed due to wide spread non-compliance. Yet it is expensive , capacity is limited and hotels aren’t great quarantine facilities in the first place. Sealed windows and shared ventilation systems in particular are problematic.
Whether or not the trade off in tracking people for two weeks is worth it, I’m not sure.
I don’t think these measures will be around permanently though. The slightest suggestion of permanent measures has been slapped down hard so far.