Australian Pricing

Is someone able to explain how Diablo 4 Standard Edition for PC costs $109.95 AUD via battle.net, but the PS5 edition is only $89 AUD via JB HI-FI?
How is it that a retail store is able to charge $20 less for a physical copy of the game with all the licensing and middlemen of playstation etc, than blizzard does for the digital version on their own client on pc?