Try asking it to summarize a draft of an essay. If the result is anything like the original, the essay is bad.
The interesting claim is that if the LLM can understand your core thesis well enough to summarize it correctly, that means your idea was conventional, because the LLM would otherwise substitute the nearest conventional thing, ignoring what you actually wrote or didn’t write.
The counterargument is that the LLM not being able to summarize correctly might also mean you did not do your job explaining. As an author, if you say nuanced unconventional things, and everyone who reads your text comes away with the same wrong reading as an LLM would, that’s you failing, and the LLM can alert you to this.