If the police want to open my phone I will supply them with the pentalobe driver to do so.

This comparison is ridiculous, the amount of private information you can gather from my mail is incomparable to the amount of information you can gather from my phone. My phone remembers more about me than I do. Conversations I don't recall having, places I don't recall going to. Open up your Google timeline and scroll through it, you'll see plenty of things that make you go "Huh I wonder what I was doing that day."

Do people normally mail their pictures to themselves? Mail is typically limited to sender -> receiver. The closest analogue to me would be a diary and unfortunately not so clear-cut: https://blogs.findlaw.com/law_and_life/2017/06/legally-is-my...