I disagree, if someone likes a restaurant then they're likely to come back even if they can get a cheaper meal elsewhere, price isn't the primary factor most people use in choosing a restaurant.
I bet the average person would go back and/or recommend the restaurant to friends if they had a good experience though.
"The 32% that said they didn’t make a profit from the program reported that customers rarely bought more than the coupon deal and few returned to the business at a later date."
If over 68% of the customers returned, then I'd call that a huge success.