Data exists in some ether that your mind never really has to deal with completely. Physical things have presence. They take up space. They can arrest your vision. When you move them they stay moved. You can fold, spindle and mutilate them as you wish.
As the next version of Confluence is nearing completion, this is particularly relevant for us right now. But it’s a great technique for focusing your development team on making it to the next release (early and often, right?).