Purpose of official with-redux example

[ashishrainagit2]

I have added the store in _app.js, simple like this:

import { Provider } from 'react-redux'
import  store  from '../store'

export default function App({ Component, pageProps }) {
  return (
    <Provider store={store}>
      <>
        <p>I'm on every page!</p>
        <Component {...pageProps} />
      </>
    </Provider>
  )
}

Store is shared when navigating client side and initial store is provided when server side(refreshing), What purpose is solved by with-redux example, Can't wrap my head around it. I understand the working , but cant understand the purpose, when we can simple add redux in _app without creating store every time and get the same functionality.

https://github.com/vercel/next.js/tree/canary/examples/with-redux