The Bankwest cards currently have no sign-on bonuses, which is a shame, because if they had those sign-on bonuses it would be a no-brainer to get one of these cards.
Assuming the valuation of a cent per Qantas FF point, you would have to spend over $41,000 in Europe to earn the points to make up the $275 annual fee on the Bankwest Qantas World card. Or you'd have to spend $32,000 on the Qantas Platinum card to cover the $160 annual fee. Of course, others value the Qantas points as worth far more when used for flight upgrades, versus straight redemptions on economy flights, which would lower the spend required to cover the annual fee.
To my mind, unless you are a big spender, point gains from using the card would be marginal at best. The 28 Degree Mastercard coupled with direct debit to your account is still a good card for avoiding international foreign exchange fees, though no points are earned.
If I was you, however, I'd also be looking for a card that would give you 12 months travel insurance for your trip, more economically than buying the insurance outright. Some cards limit the coverage to three months or six months of travel while, from memory, the CBA Diamond card gives you the full 12 months. You'd have to read a lot of Travel Insurance PDFs for each of the various cards you are considering to ensure that you are covered. I suspect savings on travel insurance relative to purchasing it outright, would be more significant than any savings that accrue from accumulating points.
Regards,
Renato