it is a mini-computer that carries every personal detail of your life, financial and otherwise.

No, it doesn't. What are they gonna do? Get phone numbers from my contact list?

unlimited access to your unlocked home computer

That also wouldn't do anything. There's nothing useful for them there. What are they doing to do? Play my games, listen to my songs, and print out my letters?

I don't lock my phone or my computer. My phone doesn't have any apps beyond Duolingo and my computer is configured to not retain any browser history (let alone to store login credentials). A random person can't use either device to get my banking information or whatever the case may be.

If the random person got access to my filing cabinet, however, then they're be trouble. That has, for example, tax documents that include my Social Security Number.