I totally agree that PoW is useful.
However, the others who are worried about the energy cost of PoW, most of them choose PoS now.
I wouldn't say I like PoS, as the soul of blockchain, is about the miners contributing resources but not capitalizing.

So, another direction we can try is to make PoW "more useful".
Assuming there are three roles:
Blockchain system, miners, and users in the system,
I can say the current PoW mining is useful to the blockchain system security.
The user cannot feel insecure unless the amount of computation is low enough (most of the miners quit).

EcoPoW is adding another usage to the existing PoW.
It did not change PoW for consensus at all.
And the PoRep/encoding with EcoPoW does not cost extra computing.
It is useful to blockchain users as proof that the data is kept by a resource (storage) provider honestly.
The storage providers (miners) can charge the users with the proof. It is the new revenue source for the miners.


The Proof of Replication and Proof of Space is different.

Proof of Replication (PoRep) does not generate consensus.
It only shows the data were kept by another user, honestly (on a dedicated storage, to prevent an OutSourcing Attack).
It saves useful user data on disk.
Filecoin uses PoRep for user data security and PoS for consensus.

Proof of Space (PoSpace/PoC) is a replacement for PoW.
It outputs consensus but no useful user data on disk.
It uses computation to pre-generate a lot of trash data on disk.
After pre-generation, there are less energy cost for the consensus generation.
Chia project uses PoSpace so it is not a blockchain storage project.