> For example, it is well known that an iCloud hack leaked the photos of many celebrity women and was dubbed "the fappening", only possible because they were stored in a viewable format without e2e.

I thought the 2014 iCloud hack was because attackers tricked users into revealing their passwords, not because Apple's iCloud service itself was compromised. If that's true, e2e would not have made a difference.

https://en.wikipedia.org/wiki/2014_celebrity_nude_photo_leak

(Of course it's definitely possible for a service itself to be hacked wholesale, in which case e2e would help.)