It is required if you want to handle zoom on device rotation.

It shares the same security as a base page.

It shares the same page parameters as the base page.

It has the same pretty URL as the base page.

copying a page with its page variants

previewing a page in different devices

adding a page parameter for just one page variant but not its base page

filtering the pages by device group

This is the only way to set a connection in ADF.

You can change the endpoints of the connections at run time.

The connections can be updated when adding the task flow to the page in Portal Builder.

Maintain all connection details in a central location.