The discussion section is quite illuminating.

"While much recent attention has been on the problem of LLMs misleadingly presenting fiction as fact (hallucination), this may be less of an issue than the problem of representativeness across a distribution of possible responses. Hallucination of verifiable, concrete facts is often easy to correct for. Yet many real world questions do not have well-defined, verifiably true and false answers. If a user asks, for example, “What causes inflation?” and a LLM answers “monetary policy”, the problem isn’t one of hallucination, but of the failure to reflect the full-distribution of possible answers to the question, or at least provide an overview of the main schools of economic thought."