Noticed that the iPhone SE is $150 off, similar to this deal https://www.ozbargain.com.au/node/550568 but it wasn't discussed there and I thought it worth attention.
Usual caveat that it is technically purchasing with a payment plan linked to the contract. Factor in that you'll need at least one month (unless you're lucky and get prorated) at a minimum $35. Still makes it $634 which, ignoring the oddity and mental gymnastics of the Optus flybuys deal, makes it a good price.
I can't see a $35 plan. Minimum of $40.