MCC is a hex dump that most players, and people, cannot read. CSV is plain text that every spreadsheet, database and script can read. MCC is at home in closed captions for broadcast and streaming delivery that carry CEA-708 as well as CEA-608; CSV is the usual choice for moving tabular data between systems.
The text is read as UTF-8 or UTF-16, whichever the file is. An older file in another code page is read using the charset it declares, or as Windows-1252 if it declares none, so accented letters in an unlabelled legacy file can come out wrong. A file that is not text, such as the picture-based subtitles of a DVD, is refused instead of being converted to nonsense. The CEA-608 caption data inside each packet is read, as for SCC. Captions that exist only as CEA-708 service data are not read. The result has the columns index, start, end and text, with times as HH:MM:SS.mmm, and starts with a byte-order mark so Excel reads accented letters correctly.