first thank you to Westpac for this $141 easy money. and credit/thanks to my friend who told me this.
Better offer was in mid of 2017 for similar cards (no annual fee first year)
https://www.ozbargain.com.au/node/316437

A Basic card so many should be able to get it. low minimum spending too. should be fine to get woolworth egift card with 5% off cashreward and then top up Opal cards and meet the requirement.
pro tip: during application it is better to specify credit limit, and select low amount (minimum is $500) unless you really want to keep this card forever (who wants????)

please use cash back exclusive link:
Help gives you 200 big ones
Get $200 cash back when you spend $400 on a new Low Rate Card within 90 days of card approval. New cards only.
https://www.westpac.com.au/personal-banking/credit-cards/low…

Card Features:
Get a low variable rate of 13.49% p.a. on purchases.
Withdraw cash at a variable rate of 19.49% p.a.
Keep costs down with a low annual card fee of $59
Pay no interest on purchases for up to 55 days when you pay off your balance in full each month.

T&C (anyone notice a typo?):
1. Cash back promotion: The cash back offer is available when you apply and are approved for a new Low Rate credit card from 18th December 2019 and 28th February 2019 and spend $400 on eligible purchases within 90 days from card approval. Eligible purchases do not include fees, cash, cash equivalent transactions, BPAY, refunds and balance transfers debited from the card account. Only one cash back will be paid per customer. The $200 cashback will be paid as a statement credit to your respective Low Rate credit card account within 60 days of meeting minimum spend criteria. Existing Westpac customers who currently hold a Low Rate credit card, or who have held one in the last 12 months and packaged cards are not eligible for this offer. Cannot be used in conjunction with the balance transfer promotion.