ADS-B is a catch all term. ADS-B is mostly US thing, ADS-B differs by country and in Canada there is no requirement for it, no idea what oz has for requirements.

There are different levels and kinds of traffic warning system that work off transponders of all kinds. Problem is you have to set the alert range on them. Thats easy in an airplane, just warn if anythings comes within 5miles. If it goes off all the time you reduce the range or end up muting it. They are far from perfect in slow moving aircraft.