That is a great question. My thought is that as an anti-humectant (Moisture blocker), it will prevent water vapor from penetratimg your hair strands so if your hair is dehydrated and longs for water, it will not be able to get it from the air/atmosphere and that would not help if you are on the journey of rehabbing/ hydrating your hair. Hope that helps.
It is completely optional. I like the additional firmness I get with bamboo ginseng, and it adds some sheen to my hair. I live in a dry climate, so I really could go without it in terms of firmness, but to be honest, I just like the overall esthetic / look of my hair when I add bamboo ginseng. I have compared with and without it, and I often go with it.
