In terms of power, it’s obvious that this ability made Homo sapiens the most powerful animal in the world, and now gives us control of the entire planet. From an ethical perspective, whether it was good or bad, that’s a far more complicated question. The key issue is that because our power depends on collective fictions, we are not good in distinguishing between fiction and reality. Humans find it very difficult to know what is real and what is just a fictional story in their own minds, and this causes a lot of disasters, wars and problems.
The best test to know whether an entity is real or fictional is the test of suffering. A nation cannot suffer, it cannot feel pain, it cannot feel fear, it has no consciousness. Even if it loses a war, the soldier suffers, the civilians suffer, but the nation cannot suffer. Similarly, a corporation cannot suffer, the pound sterling, when it loses its value, it doesn’t suffer. All these things, they’re fictions. If people bear in mind this distinction, it could improve the way we treat one another and the other animals. It’s not such a good idea to cause suffering to real entities in the service of fictional stories.