The article doesn’t go into it, but a key advantage they have is that heat pumps move heat, rather then trying to generate it. So they can move a lot more heat into your house than would be generated by running the electricity they use through a resistor. This makes them effectively more than 100% efficient (the exact amount depends on temperature) as compared with burning a fuel or resistive heat.
Technology Connections did a video on this recently. The need for backup, even in Chicago, is way over estimated.
The caveat there is that he lives in Town Home. Someone living in a stand alone home will have four exterior walls and a higher b/u heating requirement. I’d also like to point out that Chicago isn’t even close to the end all / be all of cold. He makes a big deal out of -12f but other areas in the country will go to -30 or even -40 nearly every winter.
The furnace in his place is comically oversized though.
His point was that the guidance used by sales staff tends to be far higher than design guidance in building codes. Then, he proved the design guidance two different ways to show it worked with his home.
And the design temperature of -12 °F used for testing is only 13 °F higher than the record low of -25 °F. If his system had to deal with a record low, it is still going to keep the house above freezing.
He mentions that his parents live in a single family home in the same area and get along fine with heat pump.
Plus, from personal experience, the heat pump in my SFH only started needing emergency heat when the 20 year old compressor started to go, and since I’ve replaced it I’ve never had to use the emergency coils. I do have a fire in the fireplace on very cold nights, but that’s mainly to alleviate strain on the grid.