Arjuna is a representative of a regular student , full of doubts and problems like anyone of us. It is easy to relate to the teaching by having such a student. If he was like Ashvalayana Rishi who could say Mai eva sakalm jatam after listering to 18 mantras than we cant easily relate with him.
the knowledge of shastras are like rules and guidelines to live in society. what Arjuna asked or needs is intimate , for himself. as per Dharma as a kshatriya his duty is to fight, Dharmaraj knew it so he did not hesitate to fight. what Arjuna thought was- Is war and killing worth it? I think this is the question which elevates him above all and a worthy disciple of Lord Krishna. Gita answers this intimate question- Is my suffering Real? This is the beauty of it