A standard issue Las Gun is more powerful than some people let on, they are fully capable of taking an unarmoured mans arm or head off. Also, Stub Weapons require the manufacture and delivery of ammunition to troops on the front, while Las Gun Charge Packs are capable of being recharged.
Right. I went over some lore after a few rebukes on that comment, and you are right. The Las gun is rather powerful, as well as versatile and robust. I was surprised that you can recharge it over open fire, though it isn't a good idea.