The purpose of a thing is what it does. Australia's policies do not protect children. They quite brazenly and blatantly leave children vulnerable and exploited. The question of what those actions accomplish has a simple answer - narrative control, censorship, and weaponization of public discourse against dissent.
The real solution to these problems are cultural. If you want the best outcomes for kids, then reinforce stable loving family environments, empower a culture of resilience and competence and capability, impose accountability for wrongdoing, negligence, and careless operation. If teachers and families are leaving kids vulnerable, the solution is better education and more information.
None of the policy Australia crafted does anything good. It's just another power grab using "won't you think of the children?!" as the excuse. Next year it will be terrorism or drugs or money laundering, and they'll keep constricting around civil liberties until they have absolute control.
They'll also put various racial and ethnic officials in prominent positions, so that you may not criticize anything lest you be deemed a racist or bigot (super effective social engineering.)