Consulate SurveillanceConsulate Surveillance would be playable at this cost if it prevented damage to your creatures and such, but it doesn't
For the Common Good Worst case scenario, For the Common Good is a card you use to recover after an opponent has decimated your life total
Even if the Saheeli Rai has been on the battlefield a few turns and has enough loyalty to survive a Shock immediately, after the Guardian Flickers the Sahelli back onto the battlefield, it will no longer survive the Shock, which makes having access to the red instant at all times vital
Two-for-ones also tend to excel in formats like Standard and smaller formats like Block
However, status effects like Sleep are an excellent way to throw opponents and sneakily take out the top meta cards
It's not as synergetic and strong as you'd want, as opposed to the best deck from this set at #1