My daughter’s experience was that attending class was critical. It was the best way to understand the material and what the professor considered important. Lot’s of stuff on tests were from lectures (not just books and online resources.) Many of her classes included some aspect of participation in the grading. This might be because of her major (econ and math) and the type of classes she took (mostly small number of students not big lecture hall classes.)
Also, college servees many purposes (not just grades - although a degree is the end goal) - gaining skills, learning how to think, managing your time, learning to prioritize, broadening your horizons by making contacts and interacting with different types of people, etc. All those little things that add up to being mature, independent, and responsible.