Coc and observation, not much of an advantage as armament, if you have top tier coc but no armament or observation your on the verge of being fine but still doomed, if you have top tier armament but no coc or observation you’ll be pretty fine, if you have top tier observation but no armnament or coc your kinda doomed. But if we’re talking levels of haki it has to be base observation, never really seen used. It’s basically Base Obs<Base Coc<Base Arm<Adv Coc<Adv Obs<Adv Arm. You don’t really need Coc in battle, you need arm tho, observation helps but is kinda buns if your enemy moves too fast