Food band concept is simple. Publishers donate non perishables canned food, WT tower gives it out in exchange for a future donation. Unlikely to make them a fortune but it may earn enough members. The problem with that idea is that is more likely to attract people looking for food than it is to attract new members.
I live in one of the poorest areas of the US. Average household income is about 12k a year. Many religions have come in here and offered people (specially single mothers and undocumented inmigrants) free food, homes and loans. The math is simple. Someone can work really hard to earn credit worthiness and pay a bank 14 to 18% interest on a short term loan or loose their assets or, a religion can come and offer the loan to you for free (in some cases no need to repay) and then God guilt you into giving 10% of your income for the rest of your life. What pays better?
What? did you really think that WTBTS had invented something new with this new donation arrangement?
We had several pioneers in our congo tell us the story of new interested people, who wanted to start a study. After several weeks of earning the trust of the pioneer, they asked if the church offered loans to people. When the pioneer said no, the person asked to discontinue the study. True story.