Dark traits are helpful once you are actually in the position of power. This article thought dark traits might help get you there, but this is not the case. The economic system rewards leaders who are cut throat and rewards subordinates who are kind, it makes a lot of sense when you frame it that way really.

If you are a CEO the system will reward you for paying people less wages so you can beat out competition.

If you are a worker the system will reward you for kissing the CEO's ass (by not punishing you).