In theory smart contacts remove the need for law & lawyers to enforce contracts. In practice any useful contract will need some data that isn't present in block

In theory smart contacts remove the need for law & lawyers to enforce contracts. In practice any useful contract will need some data that isn't present in blockchain, from 3rd party providers/oracles. It is nice solution for gambling - if you bet on future blockchain state, since betting on sport events need an oracle that will provide smart contract with sport event results.