First guy that mentioned post office banks to me was a British expat who also said that the post office checking account was really useful when he was a starving student. He was about 1500 pounds overdrawn when he graduated and they were still cashing his checks.

Since then I've seen post office banking as a way for getting poorer people out from under the thumb of exploitative banks, credit card companies, and check cashing places. Consider as well why should the government give a cut of EBT's cards and unemployment transactions.