reflectors are REQUIRED in my book but they are a last resort. because of the "way" in which reflectors work they tend to only really work when CLOSE to the car or when the car is about to HIT YOU. ie they are your last stand against impact but close to too late.

I would not use a bike without reflectors and I plan to add a lot more to my bike because as has been noted cheap and zero maintenance and no batteries.

but they are a last stand. not proactive. if you notice in that guys video how bright the reflectors are on those panniers. thats because the flash light is hitting them directly. To show how truly useless they are for indirect incidents when he is farther away and you can't even SEE the reflectors for all intents and purposes look what happens when the car passes him. Nothing. so if that guy swerved to the right the ONLY thing protecting you at that point are those flashing red lights.

that CENTRAL bottom one. I would like to know what light that is please that one is particularly impressive.

there are no battery excuses for lights in today's technology. RED LED's are VERY lower power consumption devices. so the only time they are a hindrance is if they use stupid coin cells. as long as they use AAA or even better AA your good for an entire season many times before you have to change batteries in those.

always use both.