I remember that light, made my Wonder in France. I used it occasionally. I think there's an important distinction between that and a front-facing tail light. I believe the leg light would make a motorist think, "Hmm, I wonder what that is. I better take a close and cautious look. Oh, it's someone on a bike." That, in turn, might lead to gentle and considerate overtaking.

A front facing tail light, I imagine, elicits, "Huh?" without any useful response.

I'm just guessing, of course.