My phone has:
* Photos going back 10+ years
* Emails going back 10+ years
* Messages going back 10+ years
* All passwords (restricted, but if you're at the border and the person tells you to open it, you'll have to)
* Access to all files on my home NAS
If you got access to my phone and wanted to snoop around, you'd get... everything, all at once, all right there for you to see. There's SO much personal data. Even in airplane mode. It's all local.
Some of it is stored in companies' clouds, but surely you see the difference between my having my emails with fastmail, files on iCloud Drive, passwords with 1Password, and... "you have direct physical access to a fully unlocked phone and can force me to unlock any part of it, and you have no restrictions, and you don't have to 'collaborate' with Apple or any other company to get that data part by part".