Tesco's Fresh and Easy, a chain that develops and operates small grocery stores that feature fresh fruit and vegetables at reasonable prices, has decided on a business strategy of locating in food deserts. This is potentially a great thing for kids who live in these places (especially if Fresh and Easy can figure out how to take WIC vouchers). But this begs the question of how they are able to sustain such a business model. Two answers present themselves--they are a non-union shop, and they rely heavily on automation. Specifically, Fresh and Easy features self check-out, and so the store doesn't have to hire checkers. Self check-out also makes it hard for Fresh and Easy to accept paper certificates, such as WIC vouchers, as payment.
So the cost of Fresh and Easy is that it may drive down wages for grocery workers a bit, and it may reduce employment for grocery workers. The benefit is that it gives low-income children access to reasonably priced, good quality, fresh foods. My personal social welfare function says to me that feeding kids inexpensively and well dominates most other considerations, but let's not pretend that there isn't a trade-off.