Writing code for what we want the page to do, not how we want the browser to do it.
I've been working on how to try and explain the fundamental difference between the following two concepts of how programming the interactions on a web page can be done. It's important to grasp both in order to understand the main benefit of React from a developer's perspective. There are also design benefits of React such as the ability to reuse and compose isolated components, but that is beyond the scope of this document.