What they said.
It\'s certainly better for basecoats, for one. But there will be times when you want less pigment -- the use of the layering technique of blending is based on a degree of transparency in your layers, thus allowing a bit of the color from the layer below to come through to give a smoother transition between the layers.
Essentially, it\'s always going to vary based on what you\'re trying to do at a particular time, whether it would be better or worse. Some times, like the above examples, are simple to distinguish -- more pigment is better when basecoating, less can be better in layering. But it\'s in getting the overall feel for it in which the learning process comes into play.