This policy disables the functionality that converts balloons to toast notifications. If you enable this policy setting, ...

This policy disables the functionality that converts balloons to toast notifications. 

If you enable this policy setting, system and application notifications will render as balloons instead of toast notifications.   

Enable this policy setting if a specific app or system component that uses balloon notifications has compatibility issues with toast notifications. 

If you disable or don't configure this policy setting, all notifications will appear as toast notifications.

A reboot is required for this policy setting to take effect.