You're ignoring the core analogy. The author's point is that someone (or something) can be verbose and articulate about a topic without having any real knowledge or experience of it. I can talk at length about war because I've seen Saving Private Ryan and read a hundred books on the topic, but do I really understand what it's like to be shot at, or to watch my friend die? No, I don't. My cousin's husband does, though, because he experienced both of those things.

The author is saying that that difference matters, that it isn't just a philosophical point but is actually a fundamental aspect of this new technology. I can spit out a bunch of words about war, and so can an LLM, but our understanding of war is limited to textual representations of it. Thomas Hobbes made this exact point centuries ago when he said, "Words are the wise man's counters but the money of fools."

As a complete aside, I don't agree that "Good Will Hunting" is a power fantasy. The whole point of the movie is that that power was illusory, and that it has nothing to do with what really matters in life.