> All they really need is backup of the data so it does not get lost. The rest of the security is out-sourced to the Bitcoin miners and the security of Proof of Work. Even the timing of the data creation is preserved by the PoW security. The data stored on the cloud node cannot be hacked

Why is only backup needed, but not security? An attacker can still gain access to the data even though he cannot change it, thus still hack it. No?