Does it really work? Most definitely. The only question is how close the plane must be to the missile to heat it sufficiently, and of course weather and atmospheric conditions factor in. The key for any laser weapon is in maintaining a coherent beam on the same spot on the missile skin for long enough to heat it up. That becomes progressively more difficult the further the laser is from the missile, and of course the beam deteriorates with distance as well.
The laser defense adds one more variable to the equation, do I or do I not launch missiles towards the United States.
The balance of power has just shifted ever so slightly once again in favor of the US.