While it's always a bit dicey to display a giant electronic smile just after you've nearly ploughed into someone at a junction, the LED Car Signal isn't as useless as it may at first seem.
How many times has somebody let you out and you've not been able to tell them "thanks" or say "sorry" to someone you've accidentally cut up. It could brighten someone's day with the selection of faces or also prompt that tailgater to "back off".