That's a great find. Revamped advertising formats might refresh the niches that were previously considered "adwords-blind."
One thing I'd like to add is that we might be underestimating Google's urge to become the reputation engine.
They might want to incorporate new layout elements to make a better use of reviews.
This is a screenshot of me pretending I'm from USA, searching for Denver Hotels:
The horizontal strip does look a bit alien and since I don't always get it, I'd assume they're still testing it.
And I don't get the Reviews Strip when I search for something else locally, like Denver Florists or Denver Barbers. So, there's plenty of room to expand. In fact, now that Google understands (sort of) the intent of the search query, it could serve the Reviews Strip for any local search.
The main question is how reliable those reviews are because we still hear stories of fake 5-star reviews being bought in bulk, nevertheless I see Google focusing on reviews more and more.