In some cases I have need of a button with additional options.
These options are typically put in a drop down associated to the button.
A split button makes this natural.
In this mode the user can click on the button itself or expand the dropdown and click on one of the options inside.
In some cases I have need of a true/false or on/off selection.
Currently I am doing that through drop down options however it would be more natural in some cases to have a switch style button.