Why make offerings of light?
In its most basic context, the act of making an offering in Buddhist tradition enables one to practice generosity in giving, to express gratitude and respect, and to contemplate on the life sustaining law of interdependence. In Buddhist teachings, all of suffering is a result not knowing and not seeing. The offering of light dispels darkness, which is the perfect allegory for the illumination of wisdom extinguishing the darkness of ignorance.
By offering light to the Buddha, it not only pays homage to his achievement of enlightenment, but it also serves as a reminder for oneself to strive for the same through the Dharma. Therefore, if one wishes to develop Dharma wisdom, he or she should offer light. The act of offering of light to the Buddha is also considered meritorious and is said to create the karma for great wealth and blessings for many hundreds or thousands of lifetimes.
Although butter lamps are the traditional form when it comes to making offerings of light, Buddhist masters will be quick to dismiss the misconception that offering traditional butter lamps is the only acceptable way. Candles, lanterns and even battery or electric-powered lamps can also be used for this purpose. In fact, Buddhist teachers advocate that whatever light is clearer and dispels darkness then it is suitable to be offered. The most important thing is having the right motivation in making the offering.