You can pair it as a sword/dagger spec to use other moves and still get riposte/concealed. With hours past midnight it can open up having 2 available exotic skills, and also it can be easier to have a wallop/batter in offhand and high damage claw in main hand. As you said above it's also good against space. And lastly it forces a double disarm to make blind/disarm a fully functional tactic.