2) Put paper in a file and come back in ten years and bugs & vermin have gotten to it, there's been a fire. Your paper no longer exists. I suppose acid free paper might help, but I've only heard about it, I've never seen it.
3) People have been editing paper for years. Look at all the trouble the banks go to secure checks and make sure people don't edit them.
The meat is rotten, but the booze is holding out. Computer translation of "The spirit is willing, but the flesh is weak."