The article states the main benefit of Peltier heat transfer is localized heating and cooling, like for your back or neck, rather than cooling the whole cabin.
Wikipedia article on Peltier effect (thermoelectric) cooling.
"Thermoelectric junctions are generally only around 5–10% as efficient as the ideal refrigerator
), compared with 40–60% achieved by conventional compression cycle"
source of 12-48 V DC conventional air conditioners. They are for trucks and trains, but it may give ideas for other searches.