> Lot of Australians can simply stop paying for power now due to free power on offer and batteries

This is overstating things.

Even if you only draw power during these three hours of the day, you still need to pay a daily supply charge, which makes up about 30%(and growing) of the average household electricity bill.

You would need about a 15 kWh battery to cover your household usage outside of these three hours.

A 13.5kWh Tesla battery system will cost about $15k installed, the taxpayer will cover about 30% of the battery cost(exc installation), which brings it down closer to $11k.

If you live an an owner occupied detached house(about 50% of Australian households), and you can afford a ~$11,000 for a battery, then you can probably pay off the battery within about 10 years.