they simply are NOT trash

Not sure what you are speaking of my friend. My favorite use was to take my two best shooters, and equip them with explosive .50 cal ammo. This allowed them to sit outside a mech cluster, and destroy the turrets and bots before they could even come into firing range

Against a huge raid of enemies, yes, they will not be quite as effective. Even if it is almost always one shot, one kill, one of 50 every couple of seconds helps, it does not turn the tides in your favor for survival. Second part of the last note, you need to find good kill zones for your snipers that are not just sitting there with the rest of your firing line that gives them good line of sight against the entire raid.

Their TRUE purpose here, is take out high priority targets. Never let a sniper just shoot randomly, until all priority targets have been taken care of. They should be who you are trying to micro for almost every one of their attacks. Doomsday rockets? Shield generators? Taking them out well outside of their effective ranges isn't just ideal, its a matter of survival with some of these weapons, and the sniper rifle category is really one of the best tools for the job

nah, ww2wonder got a point there, sniper rifles are only useful in desert or ice regions, as soon as there are a few trees its over and volume of fire becomes everything

i usally cut down every tree if i can before i start attacking and lure them into that zone otherwise my sniper might as well not participate

You can get raids where every raider has a sniper rifle of some sort.

They are very deadly.

for defense emplacements are definetly better just build one of those stationary 50 calls and shoot into a crowd of raiders. snipers are pretty good for going on raids yourself tho if you are attacking small mining sites a sniper with good stats can kill most of the outpost on their own especially if you dont bring only a 50 call but one of the faster firing ones. bringing an extra pawn with full auto is always good for back up.