Grayscale or color

So I've been watching some videos this morning from Artgerm and Boostbrush (formerly cubebrush) on grayscaling and transfering colors to a grayscale piece. I can see many benefits to the greyscale technique. It really helps the artist view the values and understand light and dark then they can easily use the gradient map. So I can understand why Artgerm and Boostbrush do it for every single illustration they have. But then I see Sakimichan who just directly adds color to her pieces. I might get this wrong but from what I've seen in short clips she directly adds color and doesn't use a gradient map?

I understand all of these artists have a good understanding of shading and color but in the long run isn't it better to just start out with a grayscale piece and then add in color?