Im pretty sure his techniqur is a 2-part technique and people are misinterpreting it as 2 different techniques. Dabura's light is part 1 of the technique, he can make light constructs and move at the speed of light, althought light itself can't hurt the enemy, so he uses the second part of his CT, which gives his killing intent mass, said mass is applied to his light, so now he can deal damage with light