Frames: Bird's eye.

Frames: Bird's eye.

A director would choose to use a bird's eye view shot because they would like the audience or viewer to gain a different perspective, therefore the director would use bird's eye view so the audience can enjoy the content from a different angle.

A director may choose to use a bird's eye view on a actor or person because they would like the audience or viewer to watch the actor from a diverse perspective or angle. The director may also choose to use bird's eye view because they would like the actor or person to be viewed from a bird's perspective. For example:

Example from the film The Avengers:                          Example from the TV show Friends:

 
A director may choose to use a bird's eye view on scenery instead of an object. This is because the director would like the audience or viewer to see a specific piece of scenery from a new perspective instead of just a 'normal' shot. For example:
Example from the film127 Hours:      Example from the film Enemy Of The State:
  
Example clip from the film Zodiac: