Personalizing any automation like that is a privacy nightmare. The system needs to know a lot about your preferences and the decisions you'd normally make yourself as well as your current circumstances since those will also influence your choices. How do you feed that into any AI without being problematic for privacy?

Having one running locally helps but it's still necessarily storing information that you might not want to have stored where someone could potentially retrieve it, either via some sort of exploit or by forcibly compelling you to give it up.