Comment by hemisphere

React allows you to keep state in components, but that doesn't mean that you should. When you're using React + Redux, keeping ANY state in components is an antipattern. Keeping all state in the "root" (the redux store) allows you to observe the your app's complete state in one place, all previous states, and the exact sequence of events that triggered all past state transitions. This discipline enables features like time-travel debugging, where you can rewind or fast-forward through your app's states one event at a time.