Yes, reflectors are only good at night, while flashing lights are visible in the day as well as night. Also, for a reflector to work, it must have light reflecting directly off of it, and into the eyes of a driver. If a rider is approaching a cross street at night, the reflectors may not be visible to drivers until the rider is actually in front of the vehicle. Lights, on the other hand, may be visible to drivers well before a rider reaches a cross street.