College courses assume a baseline of critical thinking that high school rarely teaches directly. You are expected to read primary sources critically, weigh competing arguments, tell strong evidence from weak, and write your own claims with appropriate caveats. Most students pick this up unevenly, by trial and error. Building it deliberately is faster.
The exercises suit research-intensive majors, pre-professional programmes, and any subject with heavy analytical reading. Students in those programmes report that focused practice improves grades, makes office hours more productive, and cuts the time a reading assignment takes.