Well, maybe 'obvious' is the wrong term, but there's something different between drinking a glass of milk and seeing a milk ad, and pointing out an Arcadia in a parking lot and telling your friend you liked the car, and then just later that night getting an ad for "2017 GMC Arcadia - Low Financing".

The precision is what makes it seem weird, and without an understanding of how a company would target ads to you, the idea that you're being literally listened to by the app, seems possible.