This all sounds like FUD to me. You might as easily complain about how much harder it is to refill the gas tank than swap the batteries a few times.

Lithium Ion batteries generally have a maximum optimal operating temperature of 122°F but will operate up to 176°F. If the temperature is approaching 176°F, I think the human will be the first thing to fail.

Also, nobody needs to lug around a full day of power. Spare batteries can stay in the truck until needed, at most you would have one spare on your person.