I like how the discussion is more than just what blockchains can do besides store-of-value. It's true that blockchains are just distributed databases.
We've had this solution implemented in the past using "synchronization." I used to work on databases like this, and there was always the problem of resolving database conflicts.
Blockchains solve this problem by a) enforcing determinism (which means unambiguous type definitions (which means a "date" format, for example, is defined with a certain precision)), and b) resolving these fewer conflicts quickly, using byzantine fault tolerance (which are just strategies for ensuring messages are sent to block signers reliably).
All this to say, although blockchains are just distributed databases, they are different from distributed databases when it comes to ensuring communication. A merely distributed database allows conflicts to exist and be resolved with trust. Blockchains do not require this trust.