Proof of transactions are better than the usual two set documentation, where a transaction or agreement is logged on two ledgers from the two parties making the agreement, this ledger is kept on a peer to peer system. This means that a contract or a transaction can be proven on hundreds or thousands of computers and if an alteration is made by a single party, a notification will come up. This brings a better level of security and validity. It takes away the options to make alterations to transactions, to agreements and to payments that have never been able to be in place before.
This is where the power of the decentralized public general ledger system comes in and allows for that much more proof and security.
This system is a global game changer. It goes well beyond the secure transaction between two parties. It becomes a solidified transaction, that if need be can be proven by thousands of parties.