So a hash chain. This prevents someone from arbitrarily changing a particular historical value in isolation, but there's nothing preventing the database operator from making a change and regenerating all the hashes from scratch.
The article didn't address that threat. One defense would be to make the entire hash chain available, and let a third party verify that it hasn't changed. Of course you could also replicate the entire database to the third party, so you're just gaining some efficiency and privacy (which might be worthwhile in some cases).
A blockchain on the other hand makes data really immutable. You can't change the data without doing an enormous amount of work, or (more recently) losing a large amount of staked currency.
The article didn't address that threat. One defense would be to make the entire hash chain available, and let a third party verify that it hasn't changed. Of course you could also replicate the entire database to the third party, so you're just gaining some efficiency and privacy (which might be worthwhile in some cases).
A blockchain on the other hand makes data really immutable. You can't change the data without doing an enormous amount of work, or (more recently) losing a large amount of staked currency.