Scaffold Widget is the basic structure of Material Design, and it is needed in order to render the RaisedButton Widget. Just like Container, Row, and Column, Scaffold provides the structure upon which you can render the other child widgets.
We review the following properties:
floatingActionButton
appBar
bottomNavigationBar
persistentFooterButtons
body
Sorry for the short rant. Not everyone will agree with my philosophy of documentation, and I respect that disagreement.