A really simply application of the ability to change the sensitivity of your camera, is to tame the built-in flash unit that your camera came with. I soon learnt to turn off the flash because I didn't like the "startled animal in the head lights" effect it consistently produced, even when photographing flowers!
Since changing the EV lets you change sensitivity to light, you can in effect give yourself an intensity control for your flash. The actual flash will still be same intensity but your film will see the light as less bright when you use a negative EV adjustment. This is useful when the subject is close to the camera (as these dolls where) and you need to lower the intensity of the light from the flash.
Flash with -1EV
Flash with -2EV
Similarly a positive EV adjustment will brighten a photo. This may be useful when you can not get close enough to your subject. If your subject is close this may wash them out (as it has dome with the dolls)
Flash with +1EV
The Lunimousity Histograms where produced with Ulead's PhotoImpact.
Just a final word of warning, this "apparent" flash intensity control only works when your flash is the main source of light. It doesn't work for in fill flash, because the exposure adjustment works for the whole exposure of the scene. Don't take my word of any of this go try it out yourself.