The full form of LED is a light-emitting diode; it is a small two-lead semiconductor source of light. What makes LED special is that it emits and produces light on its own compared to any other digital sign displayers. This quality of LED makes it the most durable and long-lasting technology.
LEDs are just small light bulbs that brighten up when plugged into the electric circuit. They don't have filament in them, unlike other standard light bulbs, and because of this, they never get hot or burn out. The light emitted by them is because of the movement of the electrons in this small semiconductor material. This movement also determines the color of the bulb. In other video walls, images are backlit, but LEDs produce images themselves.