Couple of points...
1. The hand-held weapon is not going to fire a continuous beam powerful enough to melt tank armor or vaporize people. It will fire a single, invisible pulse of energy--perhaps delivering a few hundred kilojoules of power in a tiny fraction of a second--and then need to recharge.
2. We already have hand-held lasers which do fire beams. Their purpose is to help aim a weapon or blind the enemy.
3. Lasers are not inherently more powerful than projectile weapons. Energy is energy, whether it is the electromagnetic burn of a laser pulse, or the kinetic impact of a bullet, which also can deliver a few hundred kilojoules of energy.
Star Trek is Not around the corner, not by a longshot.