Advantages of the Blockchain Approach

Right off the bat, the blockchain approach to non-repudiation answers one of the biggest questions for centralized services: “What happens if you shut down?”
With a centralized server, if the service goes offline, the record is completely lost. Even if there are attempts to back up the database and maintain record availability, without the trusted third party, it’s unclear how much trust the record will have. In short, the record will likely provide little help either in the court of law or the court of public opinion.

However, with a distributed blockchain, every computer on the network has a verifiable copy of the record. Even if the service that created the blockchain disappears, the blockchain itself can still provide proof.
The other advantage is that blockchain has the potential to provide a much greater amount of trust. A centralized database is only as trusted as as the entity that controls
and the records they hold mean nothing.
However, a blockchain relies on the trust of the group. As long as the group is still strong and blockchain is well distributed, the record is still valid even if the entity that created the chain initially is compromise in some way.
That is the greatest strength of blockchain, that it’s designed to survive when people are unreliable. Whether that failing is business, ethics or technology-related, the blockchain can survive.
But longevity isn’t the only thing that a non-repudiation service needs. While it’s a critical problem to solve, it’s far from the most important.