Sometimes images can be effective by blurring the subject with movement.
In the image below of the amusement park, the image was taken using a tripod, but also using a long exposure to blur the image. This exposure was of several seconds to blur the amusement ride. A slow shutter speeds can be used when you wish to gain a sense if movement or blurring of the image. In the image of the amusement park below, the shutter speed was several seconds long, allowing the lights of the wheel to move around the image.
It is very advisable when using slow shutter speeds to give some support to the camera.
The image of the ferris wheel above was given a long shutter speed to allow the movement of the ferris wheel to be captured. A tripod was used to steady the camera.