What was the importance and significance of art during the prehistoric period

While we can never be sure, I think there are some points we can deduce:

Human creativity and leisure, the urge to decorate with beautiful images beyond making tools, weapons, clothing and other utilitarian goods.

Wanting to record animals seen and often hunted for food.

A probable shamanistic and spiritual dimension: depicting animals, especially being hunted, made an act almost as “real” as the actual hunt and perhaps aligned beliefs in nature providing. These types of depictions may also be the first evidence of the power of positive thinking.

Explanation:

Years ago, I was privileged in the Northern Territory of Australia, to be taken by elders to see some ancient rock art galleries dating back 20,000 - 30,000 years. They were so huge and powerful and had an immense impact on me. How they managed to do things 30 m up and also under overhangs, was truly remarkable. Normally, these are never revealed to outsiders, however, having learned of my Māori ancestry while we were talking about our respective arts, plans were made. I had no idea what they had in mind at all. There was never any indication: I was simply taken to see these ancestral treasures, which always have a guardian on duty. The absolute power in that land and in those paintings was palpable and profoundly moving.

probably because the owner wants to get rid of it