The concept of decentralized "stablecoins" is fool's gold. It is not possible because it requires an outside source of truth (price of fiat) to be injected into the system by a trusted third party.
The reason that proof of work is absolutely necessary for both decentralization and scarcity is because the only objective source of truth available from meatspace is raw computation. Nothing else is trustlessly verifiable in cyberspace other than computation.
The reason that proof of work is absolutely necessary for both decentralization and scarcity is because the only objective source of truth available from meatspace is raw computation. Nothing else is trustlessly verifiable in cyberspace other than computation.