I don't use it anymore now that I'm natural. And my hair is fine. Every once in a while I might use an ORS pak because I like to DC with them. But never a heavy protein treatment. I agree that relaxed hair needs protein. Naturals don't really need it.
My hair doesn’t absolutely need it, but I feel my hair benefits from using protein when used in moderation. I use a mixture of eggs, conditioner, and oil as a natural protein treatment once a month and my hair loves it!