Punisher is the T1 long-range plasma battery. Built by all land/air cons it serves a very situational purpose. It can overshoot all T1 structures and units, but keep in mind that it requires a lot of metal to build. Always ask yourself if it isn't just better to spend this metal on T2.
Useful on hills, for taking down strategic targets and defending the coastline (damage boost vs ships).
Pretty useless when T2 arrives. Consider reclaiming it to get your metal back!