A heat pump is much more efficient than a resistance heater at temperatures around 10C. "California cold". A heat pump is a big deal in places like Europe, where temps between 5C and 15C are the norm.
At temperatures below freezing, a heat pump uses a resistive heater to prevent ice from forming in the heat pump's outlet airway. This resistive heating makes the heat pump less efficient at low temperatures. By about -10C, the heat pump will be about the same as resistive heating.
US EPA fuel economy/range tests include a hot cycle at 95F (45C) and a cold cycle at 20F (-6.7C). These temperature points don't benefit from a heat pump, so a heat pump will have no benefit to the EPA range rating. That's why a lot of other OEMs put heat pumps in European EVs but delete them from the US models. But even without a rated range benefit, we'll see a big real world benefit from a heat pump. In California it will be a big help from November through March, while in the Midwest or Canada it'll be a big benefit in October/November and March/April.