In GP's example, the "person who owns the database" is already trusted because they wrote the software. The software can insert lies into the blockchain very easily.

I'd also argue that the "person who owns the database" is not just trusted but also trustworthy. They have an incentive to keep lies out of the data.

If the people you can't trust are your users, then blockchain doesn't really add anything. They can insert lies, and you have to verify them. All you get is a guarantee that no one changed their lies to something else.