Banks still do what a chain does not. They create regulated deposit money and credit. They underwrite. They hold capital against losses. They run identity, sanctions and financial-crime controls. They provide a place to complain, a liquidity backstop in a stress, and a legal person who can be sued. They distribute products to people who will never read a white paper.
A ledger can record that value moved. It cannot decide that a borrower should receive credit, guarantee that an asset is enforceable in a court, or supply emergency liquidity when a market breaks. “Blockchain replaces banks” fails on the first of those jobs.