Outside my house is a crossing that waits until a gap appears in traffic before letting the pedestrian cross. Usually, by the time this happens I have already crossed the road (because a gap has appeared!).

Optimising "traffic flow" only seems to cause an obstruction for local pedestrians and cyclists. The only real purpose of a crossing is to restrict pedestrians so that excessive vehicle traffic can be accomadated. They should either prioritise pedestrians or reduce traffic.