It could be used to differentiate LLM text from pre-LLM human text maybe. The thing, our AIs may not be very good at learning but our brains are. The more we use AI, the more we integrate LLMs and other tools into our life, the more their output will influence us. I believe there was a study (or a few anecdotes) where college papers checked for AI material were marked AI written even though they were written by humans because the students used AI during their studying and learned from it.
