It is thought that Vincent van Gogh once admired the Dutch painter Frans Hals (1580-1666) for using 27 shades of black in one painting. If you study the works of the Dutch masters carefully, you can see that they actually do use very little color. (Here is an example from Rembrandt: black, red, yellow) Part of this is due to space limitations on the color palette. Pink skin tones take a lot of space, leaving not much room for other colors.
Painting above: Frans Hals, The regentesses of the Old Men’s Home in Haarlem, 1664, Oil on canvas, 170.5 x 249.5 cm
There is a similarity to designing presentation slides here. You use shades and tints of the same color to create a calm background visual, while directing the eye of the viewer with bright highlight colors to the important information on the slide.