Question about Automatic Shifters

Allright, so I have a very basic knowledge of how cars work, but I'm always eager to learn something new. So please bear with me if this is a dumb question.

My Question is this, why does an automatic transmission give you the option, like seen in the photo, to access different gears when the purpose of an automatic is to do away with the clutch and have it shift for you? I don't think you can use it like a clutchless transmission, can you?

I know for this particular model, a '09 PT Cruiser, it breaks down like this:

D (overdrive) : gears 1, 2, 3, 4

3 (drive): gears 1, 2, 3

1 (low): gears 1

Besides for hill climbing, I honestly don't see a reason why these are available. Is there certain situations why you would ever need to put the car into any other position besides D?