This is an accurate description. A teacher of students in college or high school will find in them ample opportunity to get the students started on individual research projects, should that be appropriate. Otherwise, they provide a good starting point for class discussion. This textbook is nicely laid out for classroom study. Its format and drills are less appropriate for self-study or reference, for which one would do better to select a more straightforward, traditional grammar textbook.
Errors are minor, few, and easily corrected by the alert teacher.