Ms is trying to turn Cortana into the Google play services of Windows So they can consensually(forcefully) collect data from every windows device.
Some years back Google went through a period of trying to hitch every new, and a bunch of existing, services to Google Plus.
It just so happens that the guy in charge of G+ was a former MS exec. And over at MS it was typical to attempt to hitch your project to any other project coming down the grapevine (the Google people actually called this "cookie licking" on stage after he had left the company).
And if you look back you could see this going on with .NET, you can see some semblance of this with Surface, and now with Cortana.
I guess it can be seen as some kind of in-office bandwagon politics.
I never use the "Windows Search" anymore, i hate it. It's slow and useless. I always disable the service. Then again, searching with standard windows search is probably my biggest annoyance on Windows
IIRC there were other tools: regain, lookeen, ...
[1]: https://www.mythicsoft.com/agentransack [2]: http://www.voidtools.com/
I see apparently there are workarounds to get Cortana in all regions but most people aren't going to bother. If we're getting degraded local search because of where we live that seems pretty dumb.