When/how do you use the WB skin tone tab?

I'm just trying to see if I can make C1 faster than my LR workflow since I have a slow day. I don't see the use for the Skin Tone tab under the WB tab. I put a color reading on the forehead, and then cycle through the different Skin Tones in the drop down, but I don't see any numbers changing. What is that tab for and how would you use it? If I click on the skin w/the eyedropper, it turns a horrid yellow