It's already in the public domain (thanks to the OpenAI trial) that Grok distilled OpenAIs models. Listening to the data going into the models in the data centre would be very similar thing. There's some downsides (you're passively listening, not controlling the queries), and some upsides (way more data). But it only ever gets you to some percentage of the existing production model. It doesn't get you what Musk wants - an AI company capable of designing and deploying leading edge models. It gets you to fast follower status.