Well, for a couple of reasons actually. Although you won't admit to all these right now.
React uses Components. A component is nothing but a piece of HTML code which you can reuse wherever you want to. This makes coding once a bit too easier.
Simple Learning Curve
React is easy to learn. If you know HTML, CSS and JS then you are half way through.
React uses something called a Virtual DOM whose main aim is to compare the existing DOM with the changes made and make updates using the best way possible. Yes no more hectic DOM manipulations.