I have friends and family working in Japan and requiring a stamped slip for metro delay (not sure if it's still stamped or just printed) is just a cultural thing everywhere, or so I'm told.
That kind of tradition means a lot more to Japan society than it does for some Western countries, I suppose. You can search for articles on "Japanese corporate bureaucracy" for different perspectives.
Also Japan is just about the most photographical country I've ever been to.