Pumpkin People hats

The Pumpkin People always wear pumpkin hats. They are never seen without them. The Pumpkin People even go to bed with their hats on.

Why do the Pumpkin People wear these hats? If they even wear them to bed, it can’t be just to keep their heads warm or for shade from the sun. How are they different to normal hats? And why can’t the Pumpkin People ever take them off?