[dnanian]

It's a technical limitation. When you're working with a network volume, you're working with a totally different file system - basically, a virtualized copy. You can't fully preserve all the information you need to preserve, and can't authorize sufficiently -- without an agent running on the far side -- to even write "system" owned files.

This is why both SuperDuper! and Time Machine use images as 'containers' - those images act like local drives, so we can preserve what we need to. But they can't be booted from - because they're not real drives.