Princess Zelda heard about all those "draw my life" videos on YouTube and decided to try her artistic hand at a similar one for herself. She's certainly had a... unique enough life to warrant one.
These kind of videos can be a really emotional or fascinating look into someone's personal life, but I think doing them for video game characters is a really neat idea. It's also a pretty fun way of either reminiscing about a video game or learning about one you never played. We need more of these.