Being a Mississippi resident what you call cold and what alot of the planet calls cold are to differant entities.Alot of vehicles don't get shut off where the temps are -45 or colder if you don't have access to a 120 volt outdoor plug-in to plug the block heater in,so they'll sit an idle 24/7 except to put fuel in them or check the oil.
I have not lived all my life in MS, only moved here recently. And I think the temperature in question was 50F. So not even necessary to scrape the windows free of ice.
And of course there are temperatures on this planet where Diesel fuel gums up and such. I've seen it happen. That obviously requires a different approach, then it's less about wear and tear and more about to get moving at all. But I suppose that doesn't apply to >99% of the world's population.
A block heater (at least the ones I had on RAMs) don't do much to warm up the engine to operating temperatures. They're not nearly powerful enough for that. That's for the previous point of getting underway altogether.
There are two systems that can warm up the engine without putting wear on it. Both rely on a separate pump in the cooling line that circulates and heats up the coolant to get the engine out of that harmful cold-start window. One uses the vehicle's fuel to generate heat, the other is a plug-in system that runs off electricity.