Fantasy is an important practice. We need to imagine worlds larger than our own, or else we can never imagine worlds better than our own. That's a heavy concept, I know, but I mean it. That's the whole idea of utopias. Yeah, we know they will never truly come to pass, because the world is so much messier than anything we could anticipate, but it's important to imagine them nonetheless. If we didn't, we would have nothing for which to strive.
This is why Dungeons and Dragons is fun. It forces us to think about how we would react in a situation completely different from our own. Sure, the universes in DnD are hardly utopias. They are full of crime, suffering, and mystical beasts that want to destroy us. But playing in those worlds forces us to stretch those imagination muscles. Then when we need to get together to draft a new constitution, we already have an idea of how thing could be different.