We have a long history of using firewood, which also leads to the fact that our current recipes are actually cooked for this heat.
In this way, the combustion time is longer and the heating is more uniform. So it feels more natural to eat.
Of course, another big reason is the unique smell of firewood burning. I don't know if there is any scientific research to confirm whether we have such a habit, but I smell firewood cooking, and even if I don't see it, I feel like eating it.
Perhaps it is because burning plants have a special smell, and human beings have become dependent on this smell in the process of evolution. Of course, I like the smell of firewood cooking, not the smell of burning forest.