I revise my opinion; I just wasn't getting far enough back before. I've been playing with them lately, and from a good distance back, you can effectively kill things without them getting a hit on you: like nymphs, rattlesnakes, and leprachauns.

Whenever I've used arrows or shurikens or anything like that, they don't seem to do much damage; is there something I'm missing? They seem totally useless! It seems like it would be great if they could kill a monster before it gets close enough to attack, but that never seems to happen...