Those debunks are misleading. Each one uses a different set of assumptions. In one they claim that you don’t need good insulation to use a heat pump. In another they claim that heat pumps work fine in very cold temperatures. But their source for the second claim is from countries like Norway, Finland, and Sweden which have the best insulation in the world. If you combine bad insulation with very low temperatures then the system cannot keep up.

People always worry about the worst case scenario. If your heating system is working fine for 364/365 days per year, that is a failure. On the coldest day of the year, when the temperature inside the house is dropping to uncomfortable levels and everyone is shivering while the heat pump is running at maximum (and making a lot of noise while doing so) then people will report a bad experience and clamour for their gas boiler to come back.

I have the luxury of having a dual system (gas furnace and heat pump) and I can tell you that on the coldest days of the year the heat pump cannot keep up, the furnace gets turned on automatically. The heat pump is also very noisy when it is working at full capacity. This is not the case most of the time (during shoulder seasons) but it definitely occurs during the heart of winter. My house is extremely well-insulated (though still well below Nordic standards).