The question is about Sniping Pokemon. NOT Damage Spreaders.
Sniping = One shot kills
Spreading = damageing without the knockout
Understand spreading can kill but generally it is a slow death
ie Magmortar LvX hits for 100 so it can one shot Basics, most stage 1's some stage 2
Glaceon LvX = spreads 20 to each benched. It may take 3 to 6 hits to knock a pokemon out.