What's the big deal? You don't want to join your strips together and, while pressing, discover that you have some seams facing up and some down. When you sew together 200+ inches, you don't want to sew "right" sides together and, 40 inches later, "wrong" sides together.
When you grab two strips to sew together, you just make sure the markings are on the same side.
I wish the pictures were a little clearer.