It occurs to me that when I look at the introductory compsci videos which have been coming out fairly recently... There seems to be a bias towards Computer Graphics!
I explain this by saying:
1. It films well, we can animate how these algorithms generate images.
2. Its familiar, most people have at least dabbled with implementations of these algorithms. Or seen others do so.
3. It covers a wide swath of Computer Science, due to how much data they necessarily generate!