Summary
While some of the concepts in this chapter are simple, others are a little on the tricky side. I've long said that "a good user interface makes simple things easy and hard things possible," and the unfortunate side-effect of connecting clips to other clips is that can add complexity.
While it's true that the same complexity isn't present in a track-based editing paradigm, connections allow you to move a single clip in the Primary Storyline, move its connections automatically, and be sure that all other connected clips will stay connected to their parents too. The unique parent-child connection here means that a connected clip always belongs to a parent, but that parent isn't dragged around if its child moves. It's not a locked group with both clips in charge; the primary clip is always the spine of the story.
Without connections, the lack of parent-child clip-to-clip linking means that it can be easy to lose sync between two items, or...