No beam pattern eh? How can light be seen without creating a pattern? I didn't say it was a beam pattern you needed to see from. How can a light not be meant to "cast" light? Does that not contradict the meaning of light? Look at your lights from far away. You may or may not notice that it's not filling up the space of the light housing. It's not shining out the right amount of light. It'd be similar to taking the lens off of a flashlight. This is what the diffuser does.

Let me ask you this question. Why do you think subaru put that in there in the first place?