Any discussion of programmable currencies is always going to run straight into the oracle problem. It is extremely hard to join on-chain to off-chain things wit

Any discussion of programmable currencies is always going to run straight into the oracle problem. It is extremely hard to join on-chain to off-chain things without dragging in a party that is implicitly or explicitly trusted. And the moment you do that, the purpose of cryptocurrencies goes away, as a single database run by the trusted authority is several orders of magnitude more efficient and convenient.