American Express would pay them in money, and deduct points from your account at the rate $0.01 = 1 point.
Ouch. Amex is careful not to mention that (or obfuscated it enough to hide it from me.) I keep hoping for at least a couple of cents per point for long-haul premium.
Of course the value would be enhanced if the airline accepted a low cash offer for the upgrade.
Amex says to expect to hear from the airline up to 5 hours before schedule, though 'usually 1-5 days before scheduled'. QF said you could cancel bid up to 8 hours before.