Database being a singular entity, holding up all the information, can be prone to manipulation.

I agree with most of what you said, but I just wanted to add... Nothing is beyond manipulation, there's plenty of experience out there monitoring traditional databases, and software intended to aid in tracking down tampering retroactively:

https://severalnines.com/blog/how-to-audit-postgresql-database/

Not to mention you can implement things in your application to make it even harder for a single person to tamper with the database (arguably somewhat block chain inspired), e.g.: https://stackoverflow.com/questions/1683434/detecting-database-tampering-is-it-possible

Does a ("proper") block chain make it harder to tamper in the first place? Yes, in theory, but is the associated cost really worth it? (If you ask me, the number of times it's actually worth using a blockchain is a near zero number).