Just saw this in my Amazon account. Not sure if targeted so maybe comment if it works for you or not. I have Prime and am a frequent Amazon purchaser on Visa if that matters.
Basically just need to save your debit card, Amex, Mastercard, Zip account, or Union Pay card as your default payment method, and you get a $10 Amazon AU gift card ($20 for Prime members). Can also do it by making a minimum $40 purchase on one of those payment types.
Gift card should be provided/applied to account within 30 days. Have only just done it myself so haven't received the gift card as yet.
I can't get any of the T&C links to open, so can't give much more info at this stage.
Did you have a saved payment already on your account prior to receiving this offer?