One thing worth to note is that "It does not need high energy to start a fire, but instead it needs high energy on unit area/volume (power) to start a fire". After it started, it will spread, no energy input is needed any more. It is the same principle of EM cat or EM gun. Shooting an 30 ton Aircraft needs energy in couple of kWh, nothing big, but consuming that amount within few seconds by a EM cat than 48/72 hours by a home refrigerator makes something huge. The laser gun's spot is tinny compared with a match (6 mm flat spot vs. 30mm fireball), so although the total energy may be on the same scale, the power (energy density) is hundreds times higher, making it start the fire easily at a far distance.