Some lack regular access to a computer with CD-ROM capacity. Others have the computer capability and simply prefer the book and cassette version. They do not want their students to spend so much time in front of a computer screen. Teachers who want to give home assignments know that some students will not have a computer available at home. Home school families find books easier to use when traveling.
Some students learn better with books and tapes.
The sound component is easily accessed through the click of an icon, rather the starting, stopping and rewinding of a separate cassette tape. Students can more readily identify their errors, as incorrect responses appear on the screen in red at the same time the correct responses appear. My son and daughter study the course at the same time. One works at the computer and the other uses the book. The next day, they switch.