A Root said, All the smoke will exit the attic an it will be use to preserve the shingles and smoke meat.
Too dangerous a situation. Nifty idea.
Smoke sometimes has ember that might catch the attic on fire.
Mr Google said, The height creates a stronger draft, which improves airflow and ensures efficient combustion, preventing smoke from backing up into the house. A chimney that's too short can lead to inadequate venting, fire hazards, and poor air quality