Don't know where in europe you have been, as far as I know they have no less traffic lights then the usa, if not more.
The use of TL?
In very low traffic area, I'd say that we don't need them, but on some (not sure what they are called in english) roads that are not a highway, but where a decent speed is allowed, and its a road continuing for several miles, had it not be for the traffic lights, you would have to stop at every single crossing...
I a lot of countries the lights on such a main road, are calculated that with a certain average speed, you can catch all subsequent green lights.
(Still not sure why its in the jokes section)