When you depress the swingarm to load it with opposing force, the top swings open. Then, you release your thumb, and the arm returns that force to strike the flint, sparking the flame. When you're ready to snuff it out, the top swings shut, and we're back to zero. From there, you'll probably want to do it again. And maybe again a few times after that. 

Why? Well, maybe you've got a lot of candles around the house. Or a bit of a thing for bottle rockets. Or, and this is our hunch, it's just a fun and satisfying thing to do with your hands.