Having a battery operated lamp is great for when there is a power outage and a flashlight will just not do. However, cordless table lamps are also nice to have when you need light and there are no outlets in a room. The majority of cordless lamps will generate light equivalent to roughly 35 watts, which should be more than enough to read or enjoy a game of cards.
Battery operated cordless table lamps:
Battery operated cordless table lamps pictured:
Left: Fulcrum 20020-108 8 LED Sensor Table Lamp, White
Right: Fulcrum 24412-130 12-LED Lanterna Touch, Metal, Silver
Another advantage is that you can move your lamp from a desk to a side table, or even from room to room, without having to bother with any unplugging and re-plugging of cords. The disadvantage is that you will have the change the batteries, and that means extra cost. These types of lamps are usually on the small side.