My question is in the title, I suppose…
Will I earn Qantas points with my Bankwest Platinum Mastercard buying things on ebay and using paypal with the Mastercard attached?
Yes you can. I have the same card and I used it to make online purchases (via PayPal) and i have earned the Qantas points.
In saying that, it’s been a while that I made these transactions (3-4 months ago) and not sure if the terms and conditions have changed since.