Why do we delete the largest arc? I couldn't understand the elegance of the spiral until seeing that that had been done. Deleting that largest arc breaks the

Why do we delete the largest arc? I couldn't understand the elegance of the spiral until seeing that that had been done. Deleting that largest arc breaks the self-similarity. Without it, the topmost scale becomes an S curve and doesn't match the smaller layers of branching curves. I looked at the first image for around a minute trying to find the S curves in the lower layers to establish the self-similarity.