It's a semantics game, whether something is adding moisture or sealing it, if the end result is less dry hair I don't care and I'm guilty of using these words interchangeably.

Humectant is important to distinguish because it's drawing moisture from the air...or your hair/

Coconut oil helping your hair retain protein versus a PT actually adding protein isn't as important to me since I'm protein sensitive and result is the same...might be more important to someone who has damaged hair and needs protein.