No you don’t. It’s a holdover from when files were on tapes. The logic is all inverted too. Record separators were at the beginning of a record. Group and unit separators could then be nested. You really needed a spec for whatever document you were trying to makt
You need a "spec" just the same for a CSV: does it have headers, is there a consistent column ordering, etc. Control characters work the exact same as commas and newlines, but you don't have to worry about escaping them because (unless your data is binary or recursive) the control characters won't show up in the data!
