Well if I said I made a pistol that fires 800,000,000,000 rockets per second, then I could claim the same thing by your logic.
Lasers damage things exponentially over time. Short bursts of energy will only singe the surface of something, and putting a bullet through someone would be much easier and cost much less.
Putting it into a pistol would be impossible, because even if we could assume that,
these pistols are the kind that have incredibly high power outputs, to the point in which it could melt metal with a short burst, and advanced cooling systems.
then they would not be NEARLY as compact as you portrayed them, and probably not even possible. And even if it was that size, it would be incredibly fragile and possibly fall apart.
The part that caught my eye was
incredibly high power outputs, to the point in which it could melt metal with a short burst
Wait. That means that the pistol would heat itself up to extremely high temperatures. You would only be able to use it a few times before burning your hand off.