There are some reasons you'd want to encrypt even without a secret key. One is it makes it easier to erase data (just erase the key).
It also makes bit flip errors a lot more obvious, which is another way of saying harder to ignore, so that can go either way.
Can't bit flip errors also destroy encrypted volumes much more easily?
I think it depends. Encrypted filesystems typically encrypt contents of each file separately - that way you don't need to read / write the whole disk to read it write any individual file contents. Of course that means metadata may be in plain text or may be separately encrypted - again possibly folder by folder instead of all metadata at once. Exact details would vary with different file system encryption schemes.
Whereas if you image the disk and encrypt the image properly, that gives you all the great confidentially guarantees but no random access.
> Encrypted filesystems typically encrypt contents of each file separately - that way you don't need to read / write the whole disk to read it write any individual file contents.
Ah, that's not true of "full disk encryption". It usually encrypts the disk blocks.
File-based encryption is stronger; you can use different protection classes on different files, you can use authenticated encryption, etc. iOS does it this way and I assume other systems have caught up, but don't know any in particular.
Encryption does not make bit flips obivous, authenticated encryption would.