a very tiny light on my keys would be the only thing i would go for.more than once i have fumbled around in the cold when the porch light was off to open the door.
i don't like too much bulk in my pocket so most of the gizmos from True Utility would be out.
also being retired i'm really not out and around much but i could see if someone worked and lived downtown and was on the go all the time some of those key chain tools could come in handy.