Topping up points for a reward flight

I was stuck on 29,000 Global Rewards points and desperately needed a Perth-Sydney-Melbourne-Perth flight, which costs 30,000 points. The cheapest price for an airfare was ~$716 for a 21-day advance purchase. As I am a member of Diners Club, I paid $750 to my account even though I didn’t have any balance owing. They were able to transfer the points (1.5 points per dollar) virtually straight away to Qantas (they do this twice a week), thus pushing me over the 30,000 points needed and I was able to get a free flight. I used the credit on my Diners Club to pay for my hotel accomodation (Cheap Hotels), so overall I saved over $700 by not having to purchase an airfare