In fact, many people do take advantage of this government run depository institution due to its incredible convenience. It boasts the largest network in Japan with branches and ATMs in every city, town and village throughout the country. No bank can even come close to matching its breadth. The post office offers rates that are higher than the average bank in Japan. In fact, the post office sets their rates higher than the banks to insure that they receive a continual flow of funds from the public.
Safety is another reason that people bring their yen.
As a government institution, the post office offers a much greater sense of security than the banks, which have been shaky as of late with their nagging bad loans and recent failures. In general, it works. The mail arrives almost anywhere in the country within two days, sometimes the next day. Rarely is mail lost. Therefore, the post office does not have the negative impressions that plague the U.S. system.