I went somewhere with a fireplace. Let's say the place and cookware are mine. The kitchen works with fire (gas stove), so the cookware works for gas (I've used it before for a long time).
According to my research, a gas stove can go up to +-1650C and a fireplace +-550C
I know that to cook in fire usually it's required to do it in the embers. E.G: some bricks to make a support, add a BBQ grill, and there you go (Done it. Messy because of oils dripping there, but works). But what about regular cookware which will be in touch with the embers (SUPPOSING that with regular cookware you do it that way) Imagine heating up a pot with popcorn kernels (it'd be hot enough), making some hot chocolate, etc.
My guess is that apart from getting the pots dirty and probably harming the handles if they are made out of anything different than the material the pot is made (usually hard plastic or w/e), it should work fine. Although in this site I usually ask and also experiment to try out and post the results , I really don't want to risk it this time. Temperatures are higher in a gas stove (although not constant, not everywhere in touch), so these variables make me doubt.