Depends on the workload - for light loads like drawing a desktop i am sure this is the case, but under heavy load the increased performance of a normal GPU will probably make up for the higher consumption in a shorter timeframe, compared to the ages it would take running that poor iGPU into the ground for hours (which needs the whole pc to be running that whole time with the respective base power consumption), needing cooling over a long period of time instead of increasing the fan speed for a short duration.