I like the variety of viewpoints here. It is probably true that it is sometimes a good idea for shoppers to get as much money per gig as possible. Who wants to work for nothing? But what is something, and what is nothing? Some people work in this industry and also receive other benefits. That is certainly something. For them, if earnings exceed some threshold, they might become ineligible for other benefits. This is where it gets messy.
If they exceed the earnings threshold but cannot consistently earn enough money to make up for the lost benefits, they will suffer. They might end up with nothing, such as no more housing, etc. That is something. For these people, it might make sense to have reimbursed groceries even if they do not receive a fee that is worthy of their time, energy, and skills. At least they have some groceries and whatever benefits they receive.
Are they idiots, or are they smart enough to do the math and figure out how to maximize whatever earnings and benefits they can cobble together in support of whatever lives they can manage to have? Each shopper is unique!
My garden in England is full of eating-out places, for heat waves, warm September evenings, or lunch on a chilly Christmas morning. (Mary Quant)