Or both parties could update a shared non-distributed database.
I am definitely not saying blockchain is the only or even the best way to achieve that! Just that this helps explain its appeal
I'm not saying big banks have nothing to gain, they do, but proportionally less than a smaller company that no one knows about. It allows "Bank of Mom & Pop USA" to confidentially do deals with "Little-Town Bank" Shanghai" without going through the mega-banks.