Why is pergola growing in popularity？

Why pergola is becoming more and more popular in the summer, open the roof blade of the pergola to the shading and ventilation Angle, and raise the surrounding zip screen (or open the glass sliding door), so that the pergola is in a state of ventilation and ventilation around the roof, the indoor temperature will be about 10 degrees lower than the outdoor, the humidity will be 40% to 50%, not only the indoor is not stuffy, And it feels cool. As in the tree under the cool, do not need to open the air conditioning, to get the feeling of air-conditioned room.