I would like to give a massive shout out to the fact that a foot is only 5mm off from being a light nanosecond. (Pure coincidence, but imagine if the next God emperor of America changed the foot definition by 5mm to make a truly science based unit of measurement.)

Yes, that is why it states “this is what peak thermodynamic performance.” In electronics people are taught that no device is 100% efficient because energy is lost as heat. A heater is 100% efficient because everything becomes heat.

Light is absorbed by materials and ultimately becomes heat.

The spelling made me remember this gem: https://youtu.be/HguKPVgIZL8