Should all Ubuntu Touch apps use a MainView?

Should all Ubuntu Touch apps use a MainView?

I know the MainView component is the recommended container for all widgets
that are part of an Ubuntu Touch app. However, I'd like to understand
whether it is essential to use it and what it brings to an app. From the
documentation:
MainView is the root Item that should be used for all applications. It
automatically adds a header and toolbar for its contents and can rotate
its content based on the device orientation.
Basically, I'd like to know exactly what features or properties MainView
adds to an Ubuntu Touch app and if it's a strict requirement to use it to
write convergent apps for Ubuntu.
A use case would be for an app that does not need a header.