This hut is one of the highest points in Machu Picchu [1], which allowed a caretaker to see a large stretch of the the Río Urubamba in addition to the main entrance from the Inti Punku [2], or Sun Gate.
The Caretaker’s House is built in the wayrana style, whereby one of the four walls is left completely open to promote ventilation.
Links:
[1] http://www.moon.com/destinations/peru/machu-picchu
[2] http://www.moon.com/destinations/peru/machu-picchu/machu-picchu-hikes-and-treks/inti-punku-and-inca-drawbridge