Most of the non-explosive traps were not fatal to first but infection was the greatest threat after getting into a booby trap. Most traps were targeted at the feet and legs of the soldiers, so they wouldn't die from the traps immediately. The Viet Cong knew this and to aid in infecting the wound they would soak the punji sticks used in allot of traps in human excrement for days. The excrement would get into the wound and could cause lethal infections.
The explosive traps were better at killing soldiers much faster. The grenades didn't need help in killing power. An M67 grenade has a casualty radius of 15 meters. That means anyone in 15 meters of the grenade when it goes off can die. This id why the Viet Cong didn't have to help their explosive traps in preforming.