Good post. I have seen several videos and they all reach the same conclusion. There are many household items that are more dangerous in a fire than sporting ammunition. I do keep my ammunition stored either in a heavy gauge steel chest or in plywood boxes, but this is just normal storage for me - not a requirement for safety.
When I was much younger, I was a volunteer fireman and I encountered many things that were more dangerous than ammunition: chemicals, aerosol cans, falling debris...
However, there is one caveat: a loaded weapon with a cartridge in the chamber may go off in a fire with as much muzzle velocity and energy as if you pulled the trigger. There could be some reduction due to the firearm not being constrained and therefore able to recoil freely. Something to think about.