They deliver value or productivity in the sense that the data gets written after consensus of other system in the chain and not just a single authority. This verification reduces error rates.
Also, in traditional centralized systems/databases, there is possibility of delete and edit but blockchains don't allow that. They only allow read/write. Thus, all data remains there in the form it was throughout its lifecycle.
With the above 2 approaches they add value to the data that goes into the system and can increase productivity in future.
With the above 2 approaches they add value to the data that goes into the system and can increase productivity in future.