I recently attended a talk [1] by Robert C. Martin where he spoke eloquently and astutely for over an hour on the subjects contained in the diagram on a single slide. Afterwards, I was impressed by the quality and content of the
talk, and didn't feel like I'd been hypnotised by yet another slide-by-slide "presentation".
A well-given talk should not require its contents to be summarized as it is being given. Pictures are worth a thousand words, so technical diagrams are an obvious exception (there are others) to that.
[1] https://skillsmatter.com/meetups/11368-an-evening-with-uncle...