I think it's simpler than that, and they're just trying to avoid liability.

With all of their claims about how GPT can pass the legal/medical bar etc. I wouldn't be surprised if they're eventually held accountable for some of the advice their model gives out.

This way, they're covered. Similarly, Epic could still build that feature, but they'd have to add a disclaimer like "AI generated, this does not constitute legal advice, consult a professional if needed".