None of the bolt nades kill in one shot, not even firebolt on touch of flame/viking funeral. Those need to be used in conjunction with your other tools and have a fairly long travel time the farther it needs to go, not to mention the time to ready weapons again leaves the thrower vulnerable. Additionally they will fizzle and do a simple blast with no added effects if the thrower dies before the nades land anywhere. Compared to thorn and last word with quicker and more consistent two-shot potential from instantaneous hit-scan, the bolt nades are hardly broken at all.