Why are similies and metaphors used in literture?

It is usually used to personify (make personal to the reader) the phrase. It can help the reader sustain a better understanding. E.G. The wind was like a slap in the face. This has helped the reader understand how it felt to have the wind in your face. Simile is also often used in poetry to help the reader understand the underlying metaphor. It is used to make references to other sections of the text, to help link it together in an understandable way.