> which requires minimal integration with the vehicle
My guess: maybe VW is scared of a potential "which CURRENTLY requires minimal integration with the vehicle" (I imagine that the push for more and more integration will increase in the future) and therefore decided to give it a try now and not to become passively dependent on Google.
BMW allows carplay with a monthly subscription to the rest of their services, largely because they believe that as long as you're getting the full benefit of a connected car, you'll be attached to the value - strategically, it makes no sense for them to give it away from free.
The other thing? These companies are starting to change their mind as consumers demand it as a feature.
Although to be honest, if not for the unconscionable amount of money they (or Navteq, I guess) asks for map updates, I'd be even happier just using the built-in navigation all the time.
Car manufacturers of luxury cars shy away from Android Auto partially because they believe it turns one of their main selling points and silos (advanced technology) into yet another commodity.