A worm's-eye view is a view of an object from below, as though the observer were a worm; the opposite of a bird's-eye view. A worm's eye view is used commonly for third perspective when you put one vanishing point on top, one on the left, and one on the right.
In cinematography a worm's-eye view is also useful in movie making. It is useful because it can be used as one of the camera shots/views. It is used in filming to look up to something to make an object look tall, strong and mighty.