Flowers can’t be eaten. They’re just for someone to look at. Heck most people probably don’t even look at them and buy it as a part of a ritual or formality. Does it mean the flower industry is of no benefit to society?

Most things we do are in the end just burning energy to create, move and destroy things in the process. The guys who benefit from ads buy salad from shops employing people. It’s arguable that anything that increases economic cycles is of at least some benefit to society. That’s the advantage of capitalism.