Viewing a site is impacted so much by responsive design and smaller screens make it virtually impossible to decide the best option. Switch to desktop version plugin lets the user choose their own format.
The plugin adds a function so that the user can choose on the mobile phone if the site should be in mobile view or desktop view. In many cases there might be things missing or not displaying properly and a desktop view would be preferred.
For testing ( live preview ) please use a mobile device!