I only need braces cosmetically, but if I had malocclusion, would I need braces?

Of course. By correcting malocclusions, orthodontics does more than create a beautiful smile, it creates a healthier smile.
Depends. On how severe the malocclusion is. There are cases where braces are medically needed-- meaning without them your overall health could be impacted.
Maybe. Need is subjective term. If you want your malocclusion corrected, braces would be a good option for the correction. Even with cosmetic malposition of teeth, orthodontic treatment can be a very useful treatment option. Consult your orthodontic specialist for options.
Yes. The use of braces to treat malocclusion is much greater than its use for cosmetic corrections..
Bad information. Someone's giving you bad information. If teeth look wrong (cosmetic) they need orthodontic treatment because if they don't look right, they don't fit right, they're harder to clean, they wear unevenly' they stress the supporting bone ; gums, and they contribute to jaw joint problems. If they a cosmetically compromised you have a malocclusion. See a specialist, a qualified orthodontist.