I think a lot of people are going to be disappointed to learn that situations impacting business-critical operations would be considered emergencies.
The assumption that Australia just outlawed the concept of having an on-call rotation is not supported by the article.
The article says requiring an employee to be on-call 24/7 for general purposes would indeed be illegal.
There was another example that someone could not be required to come in for a surprise shift with only a few hours of notice overnight.
But completely eliminating planned on-call rotations is not part of the goal.