It would be pretty sweet if Google made this kind of integration a generally available API.
Craigslist, AirBnB, Open311, there are a lot of location-based interactions that could be accomplished with very little friction.
I haven't updated to a Google maps version with this feature, but my current version does give me Uber fare estimation and a link to the app and these are labelled as advertisement, so I really do wonder what Uber is paying for this sort of integration.