Edit: downvote me all you want, I was responding specifically to “It has to beat a battery with a garden variety heat pump attached” of which EV heat pumps are not garden variety heat pumps, which do struggle at those temperatures. Didn’t think I had to be so pedantic.
The real benefit, in my view, to being able to charge at cold temps is to improve overall efficiency. If you have to waste some amount of power to heat the battery then that is power that could have been used to charge the car instead...
It's true that there are very cold environments (Fairbanks winters, say) where in-car thermal management won't be sufficient to keep charging rates high. But those are the same environments where you can't even start a gasoline car without an engine block heater, and I don't see many "no cars in Alaska" arguments on the internet. Everything has limits, but I don't see this battery trickery having much of a home.
Gasoline powered engines work just fine in these temperatures, although many cars come with auto ignition systems that start up the engine periodically throughout the night to keep it warm. Otherwise you might have to warm it yourself in the morning using a gasoline powered "torch" (or whatever it's called), which sometimes ends up with the car going up in flames.
So it's honestly pretty funny to read that EV work "down to -10°C". Although probably relatively few of us are desperate enough to be living in such conditions.
And in places like Fairbanks where -40 (F/C) is fairly common in the winter, even cars that merely have an engine block heater will have trouble. You need even more heating pads for the rest of the stuff under the hood of you want to keep a car reliable and healthy in that kind of climate.
Now when you move just a bit off the sea, the continental climate kicks in, and you have weeks of -15 -- -20C.
On discharging lithium chemistries at those temperatures or "easily overcame with resistive" let me say that: you just don't know what you are talking about.