STAMP, STAMP, STAMP, approved!

As mentioned in a previous post, Japan uses stamps for everything! Anything official or semi-important will have a million and one stamps on it. This stamp box is currently placed on my desk in the Kencho building. Bosses and such will come over to my desk, and fumble around this chest of treasures to find the exact stamp they are looking for. I find it completely backwards that Japan still uses stamps. Do they think it's unique? or authentic? What is it about stamps that make them so official? I would like to know the answers, seriously.