It’s not the language, it’s the business rules and history.
Why is this input file loaded and rechecked 3 times? Because 30 years ago a file load failed, breaking end of quarter reports. This was the fix: if we can read that file three times and it doesn’t change then we know it’s good
There's a comment in this thread from a former consultant that completed a 4 week COBOL bootcamp before being sent to a client to write code!