Normal lamps run on electricity, so you probably don't think much about having them on all day. But a lamp that runs on human blood? Yeah, you'll think twice about turning that on.
In order to use the Blood Lamp, you need to break the glass top. Then you drop the included tablet into the liquid, stab yourself with the broken glass and let a drop of your blood fall in. And then you get your precious light. Not so glib about light now, are you?