Enma helps Zoro to get Adv CoC by mastering his flow better. Doesn't mean that without Enma, Zoro can't use CoC lol. Take Sanji's RS for example, it activates his Exoskeleton and after the modification is completed, Sanji is able to use Germa abilities (well, most of them anyway) without having to equip the RS. Same thing here with Zoro's Enma and Adv CoC. So yes, Enma is a major reason why Zoro was able to obtain CoC coating, whoever saying Zoro can't use CoC without Enma is just insecure.