Perhaps the flowers have some power in the biological are botanical sense. It is observed directly over the bees and butterflies and indirectly over the harvest, over the mood of people, over allergy, after all. But in our case we are dealing with a euphemism, in which the Flower Power has the meaning of the Power of Goodness and Peace over the strength and anger. It comes from the vocabulary of the hippie subculture whose heyday was at the end of the 60s and who were called Flower Children. Of course, monetary relationships were strange for them, but even the hippies might be interested in the slot machine Flower Power, at least because of the accustomed design.