This is a scam pure and simple.
Applying an infra red reflective coating to a halogen capsule DOES increase the efficiency of the lamp, but only moderately. It is established technology. By reflecting otherwise wasted heat back towards the filament, less energy is needed to heat a certain sized filament, or the same energy may heat a larger filament.
The life of an incandescent lamp may be greatly extended may operating it at a lower than intended voltage. But so doing greatly reduces the efficiency.
The magic "power disk" can not alter the basic laws of physics.
If other factors remain unaltered, lower voltage lamps ARE more efficient but only slightly. Here in the UK with 240 volt lighting circuits, there would be an economic case for use of 120 volt lamps in series pairs, in practice the complication and risks of mistakes are not worth the slight improvement in efficiency.
I suspect that the promoters of these lamps are simply lying about the life or the light output, probably both.