BUT (and it's a big but), it adds a second axis of subjectvity. Already, I'm out there talking about a thing which I think is "interesting" and "worthy" subject matter of other peoples time. Now, I'm adding "and is delivered in an entertaining way".
For me - that's humour - both in the delivery, and in the slides I show. But - like anything - it doesn't always land.
And, when it doesn't -- it's a very very long awkward talk. I've been on speaking circuts where a conference goes to multiple cities (same country), and the talk went down very well in one city, and bombed in another. Things like timing matter (after lunch sucks).
Also, The author lists the requirements as "inform, educate and entertain" -- and I'd add -- "in that order". I've cut things from my talk because they were funny (IMO), but ultimately didn't support the content of the talk enough. After all -- This is a tech talk, not a standup routine.
All three are very hard to do well -- but I do agree with the author in that's it's the speakers job to do all three.