While still incredibly useful, sequential access files are a consequence of a sequential medium such as magnetic tape. Random access files, on the other hand, permit nonsequential, or random, access to the contents of a file. So why might you need random access files.
Zip archives contain files and are typically compressed to save space.
Search through the zip archive until you located the file you wanted to extract. Extract the file. Close the zip archive. On average, using this algorithm, you'd have to read half the zip archive before finding the file that you wanted to extract. Seek to the dir-entry and locate the entry for the file you want to extract from the zip archive.