I suspect that any attempts to discount for cash will be quashed, if it’s not already buried in there.
The no-surcharge rule in itself won't prevent discounts for cash:
Can businesses offer discounts on other payment methods?
Yes. Businesses can continue to offer discounts for particular payment methods. Businesses should consult their payment service provider and the ACCC guidance on appropriate pricing displays.
Removing the RBA’s prohibition on ‘no-surcharge’ rules is not intended to prevent discounts being offered to consumers for using certain payment methods.