Hibernation in the cloud

The concept seems interesting, but I suppose it can only do this locking magic for the LUKS containers it manages itself. Which is kind of a pity for two reasons:

1. File-backed loop devices aren't completely free in terms of performance, as there's at least another file system involved, which might be fragmented, etc. I'd prefer the directory-backed storage option if I were to use systemd-homed, both so I can choose my own file system and to remove the loop overhead, but then I'd lose the crypto locking feature.
2. More importantly, if the root fs isn't encrypted, or encrypted with a key that remains in RAM during suspend, wouldn't an obvious attack vector be to place a backdoor there which leaks the key or data as soon as the user unlocks /home/user again?