This policy setting specifies whether Cortana is allowed on the device. If you enable or don't configure this setting, Cortana ...

This policy setting specifies whether Cortana is allowed on the device. 
 
If you enable or don't configure this setting, Cortana will be allowed on the device. If you disable this setting, Cortana will be turned off. 
 
When Cortana is off, users will still be able to use search to find things on the device and on the Internet.