According to the reviews we hear, this thing actually works just like you’d expect. See this unboxing and demo video here. These 3D pens are becoming a common place hobbyist’s tool, while also being much cheaper than a 3D printer. As you can see in the video, it works more like hot glue, but still has a multitude of possibilities even there.
Geeky uses include custom details for cosplay costumes and accessories, quick patches for gadgets, mods for your gaming miniatures, and just about any other kind of detailed hobby. This is the closest thing to a handheld all-purpose factory you’re going to get this decade.