recently I read more about Cortana in random websites and according to them she is still in beta phase /alpha phase in certain regions and it's still not available for most of regions, Cortana analyzes the way we type, our voices and the data in our PC and sends them to Microsoft to polish up the software ,actually Cortana is more powered in the server side (according to Briana website) that's why it takes sometimes to receive the responses from her. so basically Cortana is more like a server side product, it needs internet and a Microsoft account, it sends most of our inputs to Microsoft servers, it's still in beta phase. and according to various rumors and judging by their Office service ,Microsoft is slowing moving to service side that required a subscription to consume them. so I feel like in future ,Cortana might be a paid service which required a subscription to consume. and it seems like we Windows 10 users might be its Beta testers.
Microsoft has the Cortana's plug. if we didn't pay the subscription payment,we might not be able to use Cortana since Microsoft can always pull the plug.