Siri would be a lot better if Apple mined data like Facebook, Amazon or Google do. Think about that for a moment. Siri’s not the greatest, and is actively being held back because Apple values privacy, because Apple customers value privacy.
On the other hand, Android is so open that Facebook the app manages to steal people’s call history. Not even their Facebook call history, just the regular day to day call logs from the phone without ever explicitly allowing such access.
Everyone has different reasons for choosing Apple or whatever else. Privacy is clearly one point in Apple’s favor. Call that a marketing tactic if you want, claim Tim Cook is only doing it because it helps Apple make more money, the end result is that your personal data is safer with Apple.