That's a good point. There is always a counterexample in some language, so my example wasn't meant to be too literal. On a wild supposition, I might guess the French are big on gastronomy, as were the Romans, so I could imagine their word for heat might be related to something useful. Chaud might be anciently related to our words for chowder and cauldron - a sort of useful (especially for killing parasites), not painful, heat. A sort of heat that "cuts" through branches and cold, "crusting" bread and "charring" meat to "chew" and to "consume". Like I said, total conjecture to illustrate a point.

No offense to the French, but, it could be argued that, when it comes to Golden Age naming at least, they provide plaster standards. After all, our months are named strangely for gods, emperors, and numerals; chemical elements have rather false "-gen" titles; Neptune was Planet La Verrier.

[addition:]

I just realized I have three threads running all related to the topic, "Something that kills organisms or produces change can be good and useful for the human body in one way, but not in directly-applied larger amounts".