If people on the road looking at you can see your reflectives before they can see your lights, then you need to spend a bit more on lights and/or get some more modern LEDs.
There is much in this argument, but it doesn't fully counter the case for reflectives.
It's not about what the driver sees
first. As a driver I may see one, two or more disembodied red lights ahead of me on an unlit rural A-Road. They may be some distance ahead. I am likely to have little sense of the nature, speed or position of the vehicle whose presence they are alearting me to. That will come much later.
If the rider is wearing reflectives, I will often be able to plot the shape, position, speed and type of vehicle into my thinking.
As a driver, I find it helpful to have as much visual information as I can, as early as I can. There is much, much more to this story than the simple
"I saw you/I didn't see you" issue. A light, a pair of lights, even a bank of lights will just say "Lights ahead". That's helpful in its own way, but reflectives give more clues and helpfully so.
Non-driving cyclists (or those who rarely drive) may disagree on this point, but experienced, regular drivers will generally be as one here. I do not say 'good drivers', just people who spend time passing cyclists after dark on unlit roads.
Drivers will generally prefer riders to wear reflective clothing, because it gives more visual clues, earlier in the encounter. As cyclists we share the roads with drivers. Drivers pilot big, hurty, metal deathbringers* around our roads. That being the case, why not wear something that will give the driver more of a clue?
*Not really my view of cars, but not an entirely inaccurate description despite all its excess.
