How are aerial photographs useful?

Two main reasons:-

Firstly to improve on a ground-based photograph. For example, say you photographed a house to advertise it for sale. From the ground or, even a google Aerial shot is very 'flat' and unflattering. Move the camera off the ground so that you get a bit of an angle and the image immediately becomes more appealing.

Secondly to obtain shots that are either impossible or impractical/too costly. For instance, consider a proposed development for a Property Developer. It wants a view from the future Penthouse, but currently there is a pile of rubble on the ground. A ground or mast-based camera cannot get high enough but a UAV with a camera can fly to the required height and snap away merrily. Similarly, if a building such as a Church let fall some masonry from up high, a steeplejack or Scaffolder could get up there, but a quicker solution could be an aerial craft to fly up and relay inspection images to ground allowing for a rapid damage assessment to be made.