Those wires are usually expensive because in many places you have to move tangible money around as a result. In Chile in the 2010's Banco de Chile and its coun

Those wires are usually expensive because in many places you have to move tangible money around as a result. In Chile in the 2010's Banco de Chile and its counterparties (including Banco BICE) had vaults of their own in their counterparty's complex just so they could square up all the money that moved between their customers on account of instant transfers. Sure, when Alice pays Bob, Bob pays Charlie, and Charlie pays Alice a small amount of money a lot of it cancels out. But not all, and over millions of transactions one bank can end up owing another a lot of money. You have to cash out at some point, as banks hate trusting people with money for no interest. So banks then resort to armored vehicles full of cash and gold bars so they can square up. When they're moving money they balance the cost of additional security against the risk of loss and that's what gets reflected in the bill for the bank wire.