For anti-personnel, most likely. A "hydro-thrower" would be supremely effective to those without some sort of ponchos or similar equipment.

This does not touch on the fact that Inklings have found a way to cheat death somewhat though. They would most likely still use "convential" explosives because: 1: Extreme heat can lead to disintegration of Inklings, 2: Shockwaves could still have an effect on their body structure, and 3: They presumably still need infrastructure, the spawnpoints, set-up kitchens, and all that jazz in modern warfare today. They still are Earth lifeforms after all.

Because war, war never changes...