There's a third use: alerting pedestrians who are in dedicated cycle lanes and letting them know they need to get out of the way. Not because you'd mow them down otherwise but because someone else might.
Separation of traffic into cars, bikes and legs is great, whenever possible. Just as a car shouldn't mow down a pedestrian in the road, the bike shouldn't mow down the pedestrian in a cycle lane. Doesn't mean the pedestrian shouldn't get out of the way when they're in the wrong lane.
Separation of traffic into cars, bikes and legs is great, whenever possible. Just as a car shouldn't mow down a pedestrian in the road, the bike shouldn't mow down the pedestrian in a cycle lane. Doesn't mean the pedestrian shouldn't get out of the way when they're in the wrong lane.