A data point on this.
We flew QF95 and I bid $505 ($10 over the minimum), and was successful for 3 seats into J. We were originally in PE on a sale fare. The bids were not offered on QF8 outbound, and my wife and her nephew flying home on QF93 were also not offered upgrades. Because we were using our AA numbers, the bids were cash only, no points.
As a side note, Qantas was absolutely terrific to us. My dopey wife left her phone in the seat back pocket of a domestic flight. I called the QF lounge (only number I could fine to get a human) at the airport, and she reported the plane had left the gate already for its next flight. I spoke to the QF lounge at the plane's next destination (same issue), and the lady there reported that a CSM had boarded the plane, retrieved the phone, and left it at Baggage Services where we picked it up. Simply excellent service, and I have left a detailed compliment on the QF website.^^