Maybe it's more because the privacy is largely marketing and helps with continuously shutting out competitors under the guise of privacy?

If they really cared about privacy, they would end-to-end encrypt iCloud backups [1] by default and not just when ADP is enabled, which only a small subset of users do. In fact, many technical people I know don't even realize that iCloud backups are not end-to-end encrypted. At any rate, this large hole opens a lot of data (including iMesssage) open to Apple, law enforcement, etc.

https://support.apple.com/en-us/102651

[1] And iCloud Drive, and photos, and notes, and voice memos, and wallet passes, and contacts, and reminders, and...