I guess it's because the lights turn on and off automatically. The indicator is there to tell you that the light is on. I think this is standard on all Lexus cars. It's also in my parents LX470. I can understand why the LX needs the indicator.....the headlights suck! Hmm....time for HID retrofit on the LX I just need to get them to pay for the parts.

 

Here's my guess, most of us have the Auto light feature and just leave our headlights set on that position. You never know when or if your lights are on unless that green light is on, especially during dawn and dusk hours. If you haven't done the fog light mod, you can't turn them on unless the green light is on.