Agreed, regular police shouldn't have more powerful weapons to deal with the black swan (of in Australia, white Swan) events. It is more likely to end up with accidental killings.
Each police force already has a unit that is trained in these weapons and best way to deploy them in a civilian environment.
For disaster scenarios, you have the SAS...
Hey @bengy that's right. It all seems to be a thinly veiled power grab.
Nothing like a bit of fear and ignorance to get that moving..