How to add sections & pages as one of the content sources?

Apart from just adding the basic content via editor, you can also add saved sections and pages in this widget. Content toggle widget is not just limited to normal text but you can add more to it. If you have designed & saved any pages or sections for like comparison purpose or any other then you can include those here.

Just go to Content tab > Choose which toggle you want to show them Toggle one or Toggle two > choose your content source from the dropdown > Select the section/page from the next option dropdown.

Add sections/pages

Though you cannot change the style of the selected page or section directly from here but this widget has its own styling options which you can check here.