If you add a non gift card item to your purchase of gift cards at Big W, you can apply the 10% Everyday Extra discount to your purchase which is not supposed to work on gift cards. I have just completed a purchase of Amazon gift cards and a box of tissues and the discount worked.
Why fight gang members for 10% off Amazon gift cards at Aldi when you can buy the ample stock at Big W?
Its free to signup to a new Rewards account and start a trial of Everyday Extra. So you can repeat as often as required. 30-Day Free Trial Subscription to Everyday Extra from Everyday Rewards (Then $7 Per Month).
I have only tried this with fixed denomination gift cards currently rather than variable load.
There is apparently an update being rolled out across checkouts so for some stores this hack doesnt work, but for now it seems to work in most Big W shops.
Credit to Heiks900 for originally finding that Everyday Extra 10% works on top of 10% Ultimate gift cards savings.
How to get loopholes closed.