Everyone has a different skin type.  Using a soap that is targeted to your skin type will keep the skin well balanced and properly nurtured.  For example, for sensitive skin, you don’t want to use a product that is harsh.  You need to use a gentle soap that is strengthening and nourishing to your skin.  A person who wants a deep cleanser doesn’t want a soap that is too mild because it won’t give good results.  The “by skin type” category is designed for people who need to use products that fit their specific skin types.