A New World customer who spent $200 each week over three years, and picked up a couple of hundred bonus points along the way, would have enough to get a Phillips vacuum cleaner ($380 in shops) or a Breville mixer ($400 in shops).
But consumers who swiped their card occasionally would get only minor benefits, because eligible rewards like DVDs and beauty products were not good value when bought from points, Sajtos said. "You would be better off paying cash in the open market."
The study, which did not receive commercial funding, found most rewards schemes around the world were worth much less than Fly Buys.
A Qantas point was worth about .07c, he said.
But Sajtos criticised Fly Buys for its complexity. Countdown's Onecard scheme was more transparent because it rewarded consumers with cash vouchers to spend at the store, he said. A $25 spend translated into about 19c cash back, compared with a Fly Buys point worth about 17c for every $25 spent.
Consumer NZ chief executive Sue Chetwin said it did not matter which loyalty programme you were with - shopping around for the best value was her advice. "For the past 11 years, Pak'n Save has come out as the cheapest supermarket. You should shop according to price if you want value."