At the end of the day, there's simply far more mass in a broadsword, but I don't think actual combat ever really involved blades being swung full force at each other. edge on edge. "Superior Katana" is a stupid concept anyway as neither weapon was ever designed to be used against each other.
The reason the Katana is obsessed over because it's really the only weapon that has an huge amounts of romanticism attached to it by it's parent culture. To western warriors, the sword was really just at tool, but with a Samurai, it was more an extension of himself and a physical symbol of what he was. It was also his badge of office so to speak and a sign of his status due to the fact that commoners weren't allowed to bear one.
So you take all this mysticism and transplant it to the west and in true weeb fashion, the fetishists cherry pick the elements that appeal to them and ignore all the codes of conduct that went with it, minor things like self betterment and introspection.