Though, I do have to wonder how susceptible Munitions (I'm talking Cannons/Artilery here, not missiles) are to those energy levels.. But remember, Artillery/cannons operate at speeds faster than missiles, and lasers would be a 'questionable' defense against Artillery/cannon fire. (and I would really hate to see the laser, that you can shoot out of earth's atmosphere, around the solar system, and hit a target behind the horizon and still destroy it!)
Still though, converting to 100% laser is still a foolish choice.