[gus_massa]

Let's suppose that A has to deliver chocolate icecream to B. How can a blockchain verify if the quality of the delivered icecream??? Is the chocolate concentration right? Is the quality of the chocolate good? More difficult, did it arrive melted or too frozen?

I think it's possible to use multisignature transactions to implement an escrow service that can arbitrate in case of a dispute an send forward or backwards the money. (If the buyer and seller agree, they can complete the transaction automatically.) But you are changing a court in the real word by some arbiter in the real word.

Anyway, I'm not sure if someone has a good working scheme like this.