Why might an author choose to use a third-person narrator apex?

third person view is a detached person, this can be used for many reasons. it can be used to not tell you exactly what the characters are thinking and feels and rather to describe the action more.  

An author may choose to use a third-person narrator to tell the story from many  different perspectives.

The third-person point of view is a type of storytelling in which a narrator tells all the action of their work using a third-person pronoun such as "he" or "she."

The third-person narrator can be limited so that, the narrator only relates his or her own thoughts, feelings, and knowledge of various events in the story and other characters.