4) PoS can be used as a financial weapon. If you look at HBN from another angle, its pretty much a High-Yield Investment Program.
If Goldman Sachs came out today and announced a Scrypt-based "digital bond" paying out 100% annually, they would create a billion dollar market overnight. You would get every heavy hitter dumping money into that bond just for a chance to double up.
Exactly. What happens when all tech stocks and real world companies are replaced by nothing but Goldman Sachs, financial vehicle, proof of stake coins? The world collapses. This is obviously not a sustainable model. When government gets involved making Bitcoin laws, they're either going to come down on proof of stake coins hard, or they will have the same relationship how Wall Street currently exists, to enrich insiders and screw over everyone else.
"Interest" is not really something I want to see survive in the Bitcoin protocol's future. The idea of trying to replicate the current, broken financial system is outrageous.