Why so popular?
The quality of light from the incan beam is extremely high. Incans give broad spectrum light, which is much better for color rendition than current LEDs. The A2 incan is regulated with a soft start, meaning that high quality beam is the same for the duration of battery life, and that the bulb lasts a long, long time. The incan beam reaches far enough for the vast majority of normal flashlight uses. The A2 incan beam is about quality of light, not quantity.
The dim LEDs are just right for when you don't need a lot of light and want to conserve battery power.
You basically get two lights in one: a long-lasting, low intensity light, and an extremely high quality bright beam.
Scott