Yes there is a reason. Without a resistor you have no control over the current to an LED. Bad for the LED and bad for the driver circuit. Damage is caused althought it might not be immediately apparent. The forward voltage drop is not stable with age or temprature.Why people keep on trying to remove a one cent component is beyond me. It is one of the more stupid things you can do in electronics.
Face it GM, this is a battle that will never be over or won,
As a punishment for his trickery, King Sisyphus was made to roll a huge boulder up a steep hill. Before he could reach the top, however, the massive stone would always roll back down, forcing him to begin again.