Doesn't seem like it changes anything to me. If you're in an area with coal-generated power the heat-pump is still pretty much the same energy draw as a gas furnace after accounting for powerplant efficiency and transmission losses. If your local power is gas-generated, heat pump is more efficient than a gas furnace, just not by as much as advertised. If you're at a point where you're deciding this, and heat-pumps are available at the same or lower cost as gas, and energy efficiency / emissions are your motivating factor, you should probably choose the heat pump. Sets up better for the all-electric future the author is advocating for elsewhere, and you're doing somewhere between no-worse to somewhat better than you would be with a gas furnace.
Pro-gas-furnace argument would be an economic one, hinging on the cost of electricity and natural gas as well as your total heating needs. And I'd think "can heat pump really do the job for us without too often going back to emergency electric heat" might be of some concern in colder areas.
Focusing on energy efficiency, either because you have pretty much the same electric vs. gas cost in your area or because you can afford it even if it is more expensive and just want to go with the more energy efficient option, seems like heat-pump would win or tie the vast majority of time by the author's own numbers shown in this brief article.
