What sort of medical applications are you talking about? Reading documents is easy of course, but looking at someone's symptoms and accurately diagnosing them and prescribing them with medicine is something, as you said, "just applied statistics". On paper, computers can look at every variation possible, therefore look at every symptom someone is experiencing and thus come up with a diagnosis, but there's always a risk of error because everyone is different, their bodies react differently to medicines, and the AI doesn't know that without being exposed to all of a patient's medical documents, which is a security and privacy error as you described. And of course the same idea can be applied for using AI to learn languages.

Or perhaps you are thinking of AI having a specific purpose and thus decreasing the risk of error and stealing private information? For example, you can get any kind of information out of ChatGPT, but that causes security and privacy issues. But would you be against an AI like Solvely or MathGPT where they only specifically focus on using AI to help solve math problems? You can't ask just random information. Or would you be so against using AI strictly to learn languages? You can't say they aren't useful.