It's a very useful design for a large, relatively flat, building. When you are designing a large building, you want as many rooms as possible to have natural light. It's healthier, and it's free. That means putting windows into at least one wall of the rooms. How do you do this? You have to make the buildings thinner in some way, because you can't make rooms that are 100 feet across (you could, but you probably wouldn't want to). But if you make the building longer and thinner to get as many windows into the rooms as possible, it soon becomes ridiculously long and thin. So you wrap the building around on itself in loops, or rings, or angled wings. The swastika is a natural way to do this. Another way to go is what the designer of the Pentagon did -- concentric pentagon shapes.