Well...
About the last thing I'm going to do is tell someone who's at risk of freezing to death not to do what works for them. Again, I'm not inherently apposed to batoning. It's just not the only way to skin a cat, and a generation of people educated via You Tube don't seem to understand that. If it works for you under condition X, I have no intention of trying to make you change your ways. The originator of the thread wanted to quit batoning, and my point is he never needed to start.
I've predominately carried smaller, thinner blades which I prefer for most chores. They do not lend themselves to batoning, so it's a habit I never acquired. I also grew up using an axe and started "chopping" wood when I was seven years old. I agree in principle that batoning can be safer than chopping, and for many people it's probably much safer. But if you know axes then using one safely is second nature. And last time I checked, you can strike the back of an axe with a baton too...
I'm not sure I see much difference in the thermal loss of whittling verses holding a knife and baton, but maybe there is some. Any moisture or pitch in the wood will make it much harder to carve in extreme cold, of course.
And -40 is EXTREME cold. Cold enough I'd be worried about any steel tool fracturing if it is stressed. I've spend very little time in those conditions, but a fair amount of time in the zero-degree-fahrenheit to minus-fifteen-degree range, and I DO NOT go into those conditions with only a knife and a match to start a fire. When it's that cold I'm packing a saw and a axe and a supply of tinder that will put out some real BTU's.
If I don't have my axe and saw and tinder, then I certainly didn't intend to be out in that sort of cold! The argument of "if you only have a knife" is about as valid as the argument "so you don't have your hat or mittens or boots". What are you doing there if you're not prepared? Loosing fingers and toes, most likely.
Once again: if batoning wood is your MO for fire making, baton away. But if you don't want to baton, or if you want to learn to build a fire without batoning, it hardly requires a miracle. It just requires a little different technique.