I would not say that economics is a necessity to study while in university, but it is definitely helpful and it's always great to seek advice and be taught a specific subject by people who are extremely knowledgeable in that field (of course it depends on where you go to university). There are quite a few people in this world who excelled without going to college, but I would say there are more people who did go to college and are doing great in their careers. Like I said, it's not a necessity, but it is most certainly helpful.