What is the advantage of a Masterbatch as against the traditional and conventional ways of coloring plastics?

Masterbatches were greatly popular only in the late 1970's and early 1980's. Prior to that and even today the unorganized sector still uses dry pigments and blends the polymer, additive and pigment matrix in a tumble blender and then proceeds for processing. Here there is a problem of inconsistent dispersion of the pigment and article to article color shade variation. On the other hand when a Masterbatch is used, these problems aren't faced. Plenty of time is saved.