Google seems to have rolled out a feature they have been testing for booking a hotel room directly from the Google hotel search results. I was able to replicate this myself, where I searched for hotels near me and clicked on one and it has the “Book A Room” button:
After you click on the button, it then takes you to a new screen that loads pricing from different web sites that have booking options for that hotel room for those dates.
Sergey Alakov first spotted the rollout and posted about it on Twitter.
It did come shortly after the Google My Business booking partner integration.
Forum discussion at Twitter.