This section is used as a separator between screens. So you will need it only in case you’ve chosen Papered View for your website.
You can see the Paper ID field. It’s mandatory field and it’s used for navigation needs, so it should be unique. Read more about Section ID
This section has two options: Background Color and Background Gradient Color. These settings let you choose different backgrounds for different screens. If the color is not set – the theme uses general settings from: Customizing ▸ Colors / General / Base bg color