TL;DR: if someone spies out your iPhone's passcode, they may be able to hijack other accounts synchronized with it.
In such situations, this simple passcode is like a master password, with with critical things such as PayPal and Apple Pay payments can be initiated to drain bank accounts.
Two-factor authentication also doesn't help, as their challenges can be approved easily once the iPhone is unlocked with the passcode.
https://www.wsj.com/articles/apple-iphone-security-theft-pas...
https://archive.is/tn9aq
TL;DR: if someone spies out your iPhone's passcode, they may be able to hijack other accounts synchronized with it.
In such situations, this simple passcode is like a master password, with with critical things such as PayPal and Apple Pay payments can be initiated to drain bank accounts.
Two-factor authentication also doesn't help, as their challenges can be approved easily once the iPhone is unlocked with the passcode.