They guard your data? Quote from Apples Privacy Policy about the Apple-ID:

［…］we process the following categories of personal data as necessary for purposes of our legitimate interests or those of a third party, including information about:

Your Apple ID account, including information you use to sign in, as well as all the contact, payment, and security details, such as trusted phone numbers or security questions, that you use across Apple services Your devices, including your device’s name, serial number, and other hardware identifiers Your use of, and subscriptions to, various Apple services, such as iCloud, iTunes Store, App Store, Apple Music, and Apple One Payment details, including account numbers and expiration dates, billing and shipping addresses, and gift card redemption information These legitimate interests include:

• Providing you and others with better service and support
• Using your data to send you offers via email and push notifications that may be of interest to you