Hmmm, I did not make use of much advising when I was in college, though I graduated in 4 years when the overall 4 year graduation rate was under 40%. But I did carefully read the handbook for my major (which listed degree requirements and had a handy directed graph of the prerequisite structure), and generally favored choosing courses which were the important ones in prerequisite sequences, in order to have the most flexibility later.
However, it may be that most students are not as careful at reading the written documentation about degree requirements and prerequisite sequences, so having good advising could help them. But some advisers may not give out good advice, such as the common advice to always repeat one’s AP credit (rather than suggesting that the student try the old final exams of the course that may be skipped before deciding), which can reduce the student’s future schedule flexibility. Students undecided in their majors may be particularly difficult to give good advising to, since they need to choose courses that will put them on track for all of the majors that they might decide to declare.
Perhaps academic advising can be likened to solving [critical path](Critical path method - Wikipedia) problems.