It's all looks. I purchased my ELW used with one already attached/installed. I'm still a big 'meat flag' on the highway; no special aerodynamic advantage noticed. Similar to the hole in the rear fender...
I also found a difference in air flow. It's not a fairing, but it smoothed out airflow over the front of the bike and made it slightly quieter at speed. Plus it keeps dirt and bugs out of that front gap.I put one on mine. I found a slight difference in air flow and I also liked the fact the gap between display and cowl (through which one could see the road) disappeared.