When Google don't work, then I go to the documentation, the manual or the book. To use the article's analogy, these are the equivalent of going to the supermark

When Google don't work, then I go to the documentation, the manual or the book. To use the article's analogy, these are the equivalent of going to the supermarket. If the knowledge is already in the documentation or a book, why should I keep a copy of that knowledge elsewhere, in yet another format?