Because Steel Cyclone generates enmity and heals you back for the damage you do. Plus now you can use Inner Release AND spam Steel Cyclone. But if you're wondering why I don't use Decimate instead, it's because being in Deliverance while tanking 10+ targets inside dungeons forces the healer to spam heal on you, and increases the likelihood of you dying. I'll stick with Defiance and Steel Cyclone, thanks. Save Deliverance for the bosses. It's just not worth the risk.