There is a purpose: Emotion

All art pieces require an idea, and several drafts before it can be seen as a final product. Creativity and imagination isn't all when it comes to art, technique and idea are essential to the process as well. If one of the essential parts is missing or lacks development, the art piece will suffer. The point to a piece of art is to demonstrate the artist's idea with the least amount of confusion to the audience. The purpose of art is to create an emotion, if emotion is not present all is lost.