The glow is not that bright and lasts for a limited amount of time after the bike is no longer exposed to significant amounts of light.
Reflective paint would be a much better idea, but I am under the impression that it's harder to work with. With road paint, I've been told that they spray very tiny glass beads onto the wet paint to get the high reflectance. I'm guessing that's a lot easier with a flat horizontal surface like a road than it is with a curved surface like a bike frame. Seems like it should still be doable though.