For those who don't know what's Proof-of-Replication:
https://filecoin.io/proof-of-replication.pdfIt is relatively simple to understand if you are familiar with PoW and Proof of Replication (PoRep).
I took a quick glimpse to Proof-of-Replication, and the paper essentially describes a way that nodes can prove the replication of their dedicated physical storage? Sort like Proof-of-Space Chia Network uses?
The idea is about how we can make PoW useful.
This particular sentence says a lot. You have it wrong. Proof-of-Work is already useful. It protects the network from unreliable factors. It's the, yet, unique solution to Byzantine's fault.