???
No, artists (of every animated media: 2d, 3d, stop motion, video game) intentionally put extra effort into creating ugly frames.
Not based on theory, but based on taste (artists' personal taste, or measured).
It's not a cost cutting method, not anymore. It actually requires extra effort, and it makes the product more expensive.
Maybe in animated media it is an acquired taste/coconut effect and not a way to exploit our visual system.
Either way this does not say much about whether youtube should have only sensible frames or not. But it points to the direction that (intentionally) broken, nonsensical frames in UI are worth exploring--they are everywhere in animated arts. As GP has said: "It's very possible".