[gravity13]

Yes. `useState` is essentially the "two way binding" of React at the component level. You may also enforce two way binding via an external state manager, and pass it to your React components via props.

This is the beauty of React, it's reactive style, that essentially means your UI is always bound to your state.

In Backbone, you do not get this for free, as the problem is that two-way binding in Backbone requires manual re-renders (via jQuery) which are direct DOM manipulations. This is expensive, meaning, it is not performant as your DOM grows.

React solves the problem via it's virtual DOM, which keeps an optimized DOM engine in memory, batching expensive updates onto the real DOM.

This means you get the convenience of your UI always representing your state, which means your code can become more declarative (what you want), and less imperative (what you need to do in order to get it). The author calls this "magic," but as somebody who was a Backbone main turned React main, I call this "sanity."

[Izkata]

More than batching updates, what it advertised back when React was new, was the virtual dom's diffing with lightweight nodes - it finds what changed in the tree and only alters the heavyweight DOM nodes where necessary to get the end result. At the time it was common to just swap a whole subtree when anything inside it changed, to guarantee you got everything.