This is overly simplified so not entirely accurate, but if 100 customers typo their destination IBAN the modulo 97 checksum will probably let 3 of them through.
Wikipedia says that "where used, IBANs have reduced trans-national money transfer errors to under 0.1% of total payments", although there's no source for the claim.
This is overly simplified so not entirely accurate, but if 100 customers typo their destination IBAN the modulo 97 checksum will probably let 3 of them through.