Walking sticks are herbivores. That means, they eat plants. I don't know exactly which plant these particular guys prefer, but it's something in the meadows. I haven't found them in any of my flower beds or veggies so far. Technically I guess they would be classified as a pest, though I don't believe they are causing me any problem. But I'm sure some grass or weed isn't too happy getting munched on.
I know that some species of walking sticks will eat plants that people deem valuable, but I suspect that the type we have in Hawaii prefers grass or a weed of some sort. They seem harmless to me, and I find them to be rather interesting. In fact, I think they're pretty cool. Their fragile thin legs are amazing. When these insects are disturbed they will often fold up, looking all the world like a dried bit of dead grass. When push comes to shove, they will fly off. They are not the best fliers, but they can manage to flutter several feet away. The approach of my lawnmower prompts them to take wing.
Walking sticks are one of the multitude of things that make my homestead fun. I smile every time I see one.