If you ever take the lane in front of high speed traffic like I sometimes do, you'd quickly see the benefit of a bright, flashing taillight. The sooner the drivers see me, the sooner they prepare to change lanes.* This gives the tailgater behind them more time to see me and prepare.

*or slow to my speed.

Daytime front lights are for mitigating risk form crossing traffic, and in my experience, also work well. Especially when combined with a more assertive lane position.