Comment by whyrusleeping

The proof of replication provides assurance that for some given data D, a unique replica R is created for it. What you’re proving with the Proof of SpaceTime isn’t that you have some data, you’re proving that you have the replicas. Generating the replica is slow, so you can’t do it on the fly. I gave a talk recently that goes over some of this briefly: https://youtu.be/GZZ2G9bPXsM