I think the amount is pretty good, but I wouldn't have accepted it. I expect to get the class of service for which I paid. I would happily wait for the next flight to get what I paid for, unless there was some extraordinarily rare reason for me absolutely needing to be back in Australia on the set date.
But in that circumstance, my first response would be to say "no, offload someone else". (I've been in that situation, done it, and won. Mind you, I was also a WP, which made the difference.) Second choice would be to demand that they fly me on another carrier in my ticketed class.
P.S. The pax had a BP for the sector in question, so they had given her a seat. It sounds like, because her connection was running late, they were expecting that the original flight would depart without the connecting pax, and perhaps put waitlisted pax into the seats instead of those who already had BPs. Not a great response.