Karmé is one of the main offerings that Buddhist make but not unique to Buddhists. It is an old Indian religious practice. Other religions such as Christianity also light candles. Thus, lamp offering is a common religious practice.
Buddhists consider ignorance or lack of wisdom and knowledge as the main source of all problems. The biggest problem the world faces is ignorance, which is often presented or metaphorically portrayed as darkness. Destruction of ignorance or darkness is the best thing one can do. The offering of butter lamp is the offering of wisdom and light of knowledge to eradicate darkness or ignorance. Therefore it has a crucial place in Bhutan’s daily rituals. The physical darkness symbolizes the inner darkness of ignorance and the butter lamp symbolizes the inner light of wisdom and knowledge. If one is not aware of this symbolism, the real purpose of offering butter lamps is lost.
In a world where there was no electricity, one of the best things one could give another person is light, particularly a light without much smoke and contamination such as the light from butter or oil. Other forms of creating light such as from firewood or coal emit pollutions. In this latter case, one creates light but also creates darkness through the pollution. In a society and era without electricity, butter lamp offering was a pure and precious gift one could offer to the Buddha and enlightened beings.