I think they couldn't have written that article any more confusing if they tried. They try and bounce from state to state to make it look overly complex.
In reality some states must indicate when leaving Qld, WA and NT,
Others where practical, this isn't "driver's choice", but on the circumstances such as size and shape of roundabout how many lanes, roads etc.
Then they throw in the half way around for ACT to make it sound like something unique, which actually is how then national road rules were written.
NSW only has 1 sign. The yellow is only advisory, like most yellow/black ones and has no legal obligation.
They did however forget to mention you must give way to trams!