Incredible journeys are when a purchase is immediately couple with a shutdown of the app. We've seen no sign that's happening at this point, and with the size of its install base (half billion users in one form or another), it'd be a crazy mistake for Microsoft to make.
Microsoft has already launched dozens of apps on Android and iOS, and there are several it has already bought in. That's part of its cross-platform strategy.
There's no guarantee that Microsoft won't rename an app, or incorporate the technology into an existing app, but it has no reason to pay $250m for something just to shut it down...
In this case, the acquisition was by Microsoft's Technology and Research division, not a product or service group. It seems like the goal is to integrate SwiftKey technology into many of Microsoft's mobile applications.
