When he was asked about this during the Q&A session he explained how he wanted to control the way the audience read the cartoons, so we didn’t all rush to the final slide.
This reminded me of my first training course in public speaking many years ago. Our trainer insisted that only by using view-foils could we control the content of the presentation on the fly. In other words you could add or remove content without your audience being aware of changes you were making. This is crucial if your timing starts going out due to interruptions or other factors outside your control.
How many PowerPoint presentations have you been to where the speaker starts rushing through their slides, and you sit there wondering what you are missing as they whiz by?