First the batteries are there to support the power requirement of the LED. Remember that LED stands for Light Emitting Diode. So the bigger the Diode, the more more the power required to support. There are lots of torches out there using 4 AA, 3,4, or 6 C cell batteries. It is important to note that these "bulbs" (diodes) are very durable and require less power than others (hence increased battery life). They are however, more expensive. The halogen bulbs are more brittle, but less expensive. The cost is the primary reason that most of the larger lights are halogen, and not LED
This may be me being "picky", but the reflector focuses the light beam. The light is already there, it is the beam of light that requires attention. For that is what is used for signaling.
All right, I am now officailly a geek!!