To me, our habit of "projecting our own nature onto nature," to quote Sagan once more, seems trivializing, and it is the height of arrogance to imagine that it was all created just for us.
It's how the brain works. Religion is a form of superstition, and superstition is the result of pattern recognition and the fact that the brain does not get the whole picture. A lightning strikes just when you did something wrong. And suddenly there is the thought that someone watched you and caused that lighting strike. Because the brain badly WANTS to make sense of it. And the simplest explanation is that "someone did it".