There are 2 reasons. 1 is they are not allowed fans at WI games so this is a chance to see their team. The second and biggest reason is too political to mention here. Let's just say some folks enjoy restrictions more than others.
Actually it would ALWAYS break the ties. You can't tie best of 3 head to head.
I really think a new tradition of playing each division #2 at #1 and number #4 at #3 would be a perfect17th game. I haven't seen anyone else suggest that before, though you'd think it would be an obvious thing. Basically it becomes a Division championship game, thou I understand that it ight not matter but there's a better chance of 3-4 very meaningful week 18 games.