Working at a large bank, a Cobol programmer once told me the use cases are very narrow, but that it's extremely dependable once deployed into production. To be a little blunt though, to process statements and track transactions with high dependability, it works well when you repel anyone with a low attention span or someone has a strong desire for learning new languages and programming paradigms. You need and want programmers who are more about making the same kind of sausage day in day out rather than innovation because at the end of the day, the bank statement and transactions are trivial but extremely important problems. In other words, it's an older programmer's workshop.