Pulse grenades are thrown EMP weapons. When they detonate, they emit a powerful electromagnetic burst which is only mildly harmful to organics, but can cripple anything with an electronic circuit. Thus, these high-tech grenades are "silver bullets" against robots, but worthless against anything else. If at all possible, the throw should be angled using a wall as a backstop in case of bouncing - the blast is large, but worth being put where one cannot miss.
Even though pulse grenades are near-useless against non-player character critters that all have EMP resistance, the player character critter is an exception. This means full damage from pulse grenades will be taken without any armor.