Dunno that its worth replying to ACs, but anyway... just FYI I've lived here for the past 15 years and have been involved in the hotel industry for the past 7 of of those, so have quite broad experience trying to assist guests in getting hold of cash. Even to the point of doing things like exchanging Paypal payments for cash after driving them to all the usual suspect ATMs in town. I'll give you that it was a little hyperbolic in the sense that although the 711 service has been available for longer, its only in the past 2years that we've really been able to list it as an option for getting cash in our correspondence - before that we had to have a highlighted warning in our emails cautioning people to bring cash. For example 3 years ago ALL Mastercard service was discontinued for about 8 months through 7-11.
A significant proportion of Post Offices don't even have ATMs and its only the main ones that are open until 7pm, with most closing at 5. Banks transfers, even between accounts on the same local bank will only happen during business hours, excluding Saturdays. My local bank ATMs all close at 7pm and despite the 7-11 ATMs, of my 3 Japanese bank accounts, there's only one that I can actually draw money from between 7pm and 7am.
There's quite a bit more to Japan than the Tokyo/Osaka experience...