The cynical-me is trying to work out what Qantas gains from this. Aside from the empty fluff of further supporting the already well-worn and obvious "everyone get vaccinated [so we can get back to business narrative]" and a smidge of good PR for a few minutes. There is no real incentive here, and the "rewards" are effectively useless unless you're one of the half dozen major prizes winners.
I'm sure they're interested in the data on what proportion of high status flyers are vaccinated and any potential data analysis there, but it is pretty likely we will hit that 80% mark nationally, and likely frequent flyers will be higher than that, so kind of pointless unless they're worried Gold/Platinums are somehow disproportionately anti-vax (unlikely).
At the end of the day, this is a nothing offer, and only really worth it for a chance at the major prizes(which the odds are pretty good for people in ACT/NT/TAS).
Really only tossing up between points for the $20 voucher here...