Our ancestors have knowledge of time. They can predict future changes. That gave them power to control the environment. As a result they were able to build some of the most amazing monuments in the history of human civilization that surprise us even today.
Today time is used to keep track of our work. For our ancestor they have to keep track of time in order to survive. By understanding the star cycle, which control seasons in earth, enables human race transform from hunter to gatherer.
All great ancient civilization Inca, Mayan, Babylonian watched sky with great importance and built enormous monument to observe them. Ancient people could not build those monuments without careful observation of stars.