In the 1970’s and 1980’s there were several books the either had characters that did it or promoted it.
Why is there no cooking tray in my new car’s engine bay?
Is it dangerous? (It would be less physically dangerous if there was a specific spot for it.)
While I don’t disagree, this is a line of thought that is used to talk people out of everything, including many things we do commonly.
Temperature control is less important for many baking items (potatoes, some casseroles) than modern recipes indicate. Modern temperature control is “easy”, but not needed for many things. Temperature control is critical for a few things, and those would be a bad match.