Why is a pinhole camera useful to your world?

Each single ray of light that reflects from a single point on an object does so in an infinite number of directions. The job of a lens is to gather and focus as many of these rays, which have slightly different angles of incidence, as possible. Since there is no lens in a pinhole camera, the method of control is to allow only a few of the rays from a single point that are close in angles of incidence to pass and land close together on the image plane. This can only be done by using a small opening.