in fact, if your eyes indeed are well adjusted to the dark, you will find very little need for a low level light source of this type. You will be able to do just fine by starlight, to say nothing of a full moon.
They say it is designed for "an enclosed environment", "in a tent, camper, bedroom, etc". It might be a useful backup for cavers, but otherwise it looks more like a camper's tool than a survival one.