Why is this the answer?

The answer is paper because this clever riddle describes one of the most important inventions we use for keeping and sharing information. Let's explore each clue to see how they lead straight to paper. The first part tells us that this object "holds most knowledge that has ever been said. But is not the brain, is not the head." Think about a big library or a school classroom. The knowledge in those places comes from books, journals, and documents. Paper is what holds all of the letters, numbers, and pictures that make up that knowledge. It's like a huge, flat vault for ideas. Even though it stores more facts than almost any person, paper does not have a brain or a head, so it can only keep the knowledge, not think about it. The middle clue is a fantastic word puzzle: "To feathers and their masters, it's both bane and boon." This part makes us think about writing tools from long ago. Before there were ballpoint pens and pencils, writers used sharp feathers called quills to dip in ink and write. These quills, or "feathers," and their "masters" (the people writing) have a complicated relationship with paper. Paper is a huge advantage, or "boon," because it gives them a clean place to write down their thoughts, sign contracts, or draw maps. But paper can also be a cause of trouble, or "bane." Imagine a law written on paper that is unfair, or a very important message that is accidentally lost or torn. For the person who wrote it, the paper suddenly becomes a big problem. The last part of the riddle gives us a final, clear hint: "One empty, and one full." This is a perfect way to talk about the simple life of a piece of paper. When you first pick it up from a stack, the paper is blank and empty. As soon as you put your crayons or a pen to it, it starts to become full of colors and words. It is ready to be a clean slate until you decide to fill it up with your own knowledge and creativity. All these clever descriptions together paint a wonderful picture of the simple but powerful sheet of paper.