Every premises with an address is a customer of Australia Post whether they send or receive mail, they just don't all transact on the same day.  Financial software is far more complex and important than a label printing platform, yet printing labels is less reliable than funds transactions.

The value and importance of Australia Post's fundamental job of delivering mail has been demonstrated during the pandemic.  Maybe this situation will make it's single shareholder focus on that fundamental instead of 'transforming' it into other areas far removed from 'delivery'.