Studies (believe them if you like) show that the number-one indicator of a bicycle for a driver is a pedal reflector or a light on the ankle.
Some lighting give s some chance that a driver will know there is Something ahead.
Again, it rests on the driver. idiots and mule-holes will endanger others accidentally or out of spite, most drivers will avoid incidents.
Don't really care what other cyclists do .... like the rest of you, I have a set-up which makes me feel safe enough and so far I haven't been killed. We could always mount more lights .... and after an accident, should one happen, we can always wonder if more lights (or some other thing) might have made a difference.
As with bike locks, most of what we are buying is peace of mind and a little bit of protection against the the majority of drivers, which may or may not even be needed. (After all, I am sure many of us have spotted ninja riders in our headlights and taken avoidance actions .... )