Weight, energy, cost, maintenance, ambient lighting all add into this. There are two things you need biking at night. You need to see and you need to be seen. Reflectors do nothing to see and have a limit to how well you are seen. They are designed to be retro reflective and all the methods they use have different degrees of dispersion but in general they send light back to the source. In the case of cars the source is close to the line of the driver’s vision. The greater the distance the less the angular error. The good news is cars have very bright and reflectors let them see you at a very great distance. Once the driver sees something they become engaged in the thought process of thinking about you being out there. The benefit of reflective tapes is they have almost no weight and lots of surface area. They don’t replace lights but I have 400 square inches about of reflective tape on my bike and I wouldn’t want to haul around that much light producing equipment just to be seen. On the other hand I like lights to see by. Depending on your speed and stopping distance that’s how much front facing light you need to be safe. Back facing lights blinking do something reflectors cant and that’s blink. That blinking also causes the person seeing it to start thinking.

On my bike I actually feel much safer at night than day. I see cars coming up on me to start reacting much greater at night than during the day.

The other light related thing is seeing and a mirror at night is a must. Knowing when to move over is major when being overtaken.