Is this just a case of this uneasy friendliness that MS has had recently toward the open ecosystem, or is MS trying to play a big-league game to combat Google Map's dominance?
Microsoft gave OSM permission to use their aerial imagery for tracing in November 2010. If you look at this as a continuation of that it isn't terribly recent.
Microsoft is big in the public sector in Europe, as in, really really big. Open street map is big in the public sector in Europe, as in really really big.
It's both. Microsoft is all in on cloud services and infrastructure. They want full ecosystem for Azure customers, and GeoAPIs are important for many users.
Next, with upcoming HoloLens they want devs to create some amazing real-time lens apps.