In essence, a smart contract is just a server script that controls your wallet. It's public, i.e. the code is visible to everyone and you can't change it after

In essence, a smart contract is just a server script that controls your wallet. It's public, i.e. the code is visible to everyone and you can't change it after publishing to the blockchain. The execution of this script also has some memory state on the blockchain, which is also public and controlled only by the script. That's all. Yes, you can use it to write crypto-kitties or some fair casinos (although it's very hard, since you have to implement fair unpredictable randomness). You can use your imagination to write some other interesting stuff. But you can't rebuild the entire financial system based on that. Here I commented about some specific problems https://news.ycombinator.com/item?id=27651377 https://news.ycombinator.com/item?id=27651377