Fire also sets the ground on fire. This fire can be stacked up multiple times, burning hotter and longer. A good blaze can deal over 1000 damage, which is nothing to scoff at.
Anything hit by the fire hose gets a flame debuff. The debuff deals 100 damage per second, for 30 seconds! Anything less than a behemoth biter gets an instant death sentence, and a single flamethrower research seals its fate.
What's your opinion on fire?