It is effectively a database with specific features.

A blockchain isn't magic, I'm currently working on a project with the royal mint that will be used for correspondent banking applications.

Think of it this way you have a database that is guaranteed to be consistent across all nodes, offers you full tracking of any action performed on that database, offers you non-repudiation and much more.

Sure you can probably hack it over an existing standard DB but at what cost?

Blockchain has a lot of distinct advantages when things need a very clear audit trail. Auditors love the fact that a block can't be modified without recalculating all subsequent blocks. Of course, in a blockchain controlled by a single private entity, the entity could redo all the blocks, but that's not really the main concern. The concern is to try to prevent rogue individuals from modifying the ledger without detection, and that is harder to do with blockchain than plain DB access controls.

Blimey! Here I thought any database server worth a rusty copper can do a detailed, queryable audit log / trail if that's what you need.

At least MySQL, PostgreSQL, SQL Server, DB2, Oracle surely can.

Come on, it's not difficult to see how those DB solutions are easier to modify after the fact without detection than a blockchain-based solution, and blockchain-based solutions are generally easier to make distributed while still guaranteeing immutability.

There's no reason to use a blockchain within a single entity. Use a database for that.

Private blockchains do appear to be useful among a consortium of companies who don't completely trust each other, and don't want to pay a single company to maintain a central database.

It's not about "trust" it's that keeping the accounts and books consolidated even within a single bank is problematic and between banks even more so.

Banks lose billions each year and i mean lose as they have no idea where the money went. Account consolidation within a bank is a huge enterprise.

Even within a single entity like a bank a blockchain that governs all accounts and transactions is hugely beneficial because of the consistency and the trail any action within it leaves.

Interesting. I hadn't thought through the scale of a large bank.