The bull bar has stayed legal in Australia due to their usefulness in the rural areas and the large off-roading enthusiast community. And the Hilux itself has many different types of bullbar Hilux bars usually have integrated into their design winches and floodlights which increase its usefulness on their own. But the main purpose of a bullbar is the vehicle's protection for the bonnet and the front bumper from damage, be it an animal attack (from kangaroos especially) or a very bumpy road.
One hobby that the average Aussie partakes in regularly is off-roading, this is because the landscape is vast and allows for expansive dirt roads that go through the most popular camping destinations. Which is why 4WD vehicles are very common in Australia, they are used for both work and fun by many across the nation. And a bullbar Hilux or any other model can assuredly save your vehicle frin the dangers that wilderness poses to the pickup.
However to ensure that your bullbar is protecting your vehicle and not causing you damage there are some general guidelines that you should follow. One such guideline is the angle and height of the bar, it needs to be non-obstructive to the driver's view and angled facing the vehicle. By doing this you are allowing your vehicle's crumple zone to do what its supposed to and dampen the blow to both you and (in the worst case scenario) the person or animal you've hit.
The profile of the bullbar is also very significant when checking its legality. As mentioned previously the angle needs to be towards the vehicle to ensure that it dampens rather than outright stops a blow, because the biggest danger of a crash is the inertia of the sudden stop in momentum.