Mainly this kumkuma archana is done only to female deities. Even the whole LS can be performed with kumkum. As naga ji said, its the sign of wealth and prosperity. Even for the kumkum, turmeric is the basic, which has medicinal and aromatic properties. Instead of flowers, it can be used. When the flowers were in scarce in between the archana, it can be done with kumkum as a substitute. Instead, the whole archna can be done with kumkum itself. Later this kumkum can be used as prasadam. The flowers will get dried, whereas the kumkuma archana can be done with even the same kumkum again... These are the special characters of this. Also when kumkum is with us, there is no need for us to expect or search for flowers when we are new to a place. Kumkum makes our archana simplest when compared to the flower-based archana.
Pranams