For stuff outside, they just don't have problems with vandalism and theft the way America does, so it makes it much more feasible to have lots of vending machines outside: no one is going to deface them or break into them.

This is also really useful for bicycling. Bikes in Japan all seem to have little locks on the back which go through the rear wheel's spokes, so someone can't just hop on and pedal away. But there's nothing stopping someone from picking the bike up and carrying it away, putting it on a truck, etc. But theft is almost nonexistent in Japan, so people just leave their bike parked on the sidewalk and don't worry about it, and this makes biking very easy and feasible, whereas in the US you have to worry about someone stealing it if it isn't U-locked to something completely immovable, and even then someone might steal parts off of it.