Why did te author most likely use dialogue instead of description?

To show who the characters are.

Explanation:

Dialogue is a literary technique that shows what two or more characters are saying, (it can also be between only one character and his thoughts). This literary technique allows the author to simplify the lecture for the reader, we can digest dialogue more easily than description, it highlights personalities of the characters in the story and keeps the reader entertained because of the intrigue of what the other character is going to reply. In a narrative it is important to keep balanced the descriptions and the dialogues, in this passage we can see that the author balances the dialogue accompanied by the description of each character to allow the reader to know what they look like.