For most American families decorating for the Holidays is a holiday tradition. It makes family and friends come to life.
There is a feeling of giving, which results in receiving.
Same thing happens when you decide to sell your home. It's time to decorate and stage for the upcoming event.
Why, because people only know what they see, they usually don't know what it could be.
This is another reason why experienced builders don't put their inventory on the market until it's fully completed and decorated, just like it's Christmas everyday.