Heat pumps only work on their own in mild climates. Cold climates still require furnace in conjunction with the heat pump. Good luck convincing anyone in the northern United States of getting rid of their furnace or hot water heater. Spouting this sort of head-in-the-clouds, wrong information only weakens your cause.

“WHERE DO HEAT PUMPS WORK BEST? Heat pumps are more common in milder climates, where the temperature does not typically drop below freezing. In colder regions, *they can also be combined with furnaces*for energy-efficient heating on all but the coldest days. When the temperature outside drops too low for the heat pump to operate effectively, the system will instead use the furnace to generate heat. This kind of system is often called a dual fuel system – it is very energy efficient and cost effective.”

https://www.carrier.com/residential/en/us/products/heat-pump...