>>Once a smart contract is included in a block, it has finished executing and is irreversible. The transaction is irreversible, again, by definition. The trans

>>Once a smart contract is included in a block, it has finished executing and is irreversible. The transaction is irreversible, again, by definition. The transaction is irreversible, in the sense that it can't be removed from the blockchain, but the transfer from person A to person B can be made reversible, via a smart contract that doesn't allow person B to withdraw from the smart contract for a duration, during which time person A can effect a reversal transaction that would effectively undo the transfer. >>So you're no longer using a blockchain. In my example, you are using the blockchain in all cases. You are just using smart contracts in a way that reduces some of disadvantages of naive blockchain use (e.g. allowing a consumer to dispute a fraudulent charge) while giving up some of its advantages (e.g. reduced risk of charge backs for honest merchants).