I think that is the main reason people are doing them. Easy report and something DIFFERENT than the normal crap people are doing them. Spending $15-$20 for sit down service meal for what can feed 2 (or more) is very reasonable. I know I would rather have the entire meal paid for and make money, but when you get tired of doing fast food shops and want something different, this was a nice alternative. I would do this shop all day every day over doing a 5 guys for $9 pay and not enough reimbursement. Yes, I would be in the positive even after paying out of pocket for the additional cost of the food, but I wouldn't be stuck with a crap 5 guys report and only feeding 1 person (even though I enjoy 5 guys food).
People who only want to be "net positive income" after each shop will never look at it that way. I used to be like that and I am much more picky with my shops now given my much improved financial situation. So spending $15 isn't an issue for me if it means I'm going to get more value out of my effort.