As a firefighter, I've learned that the hotter the fire burns the less CO and other noxious gasses are let out. In the end, no matter how hot the fire is, the by-product of CO still remains. The fire in that picture looks pretty hot. With a fire that hot there will be little carbon build-up or smoke. With no smoke, there's no real advantage of a wood burning grill.
Cheers, Christopher A. Kinkade, Griffith, IN USA
"The difference between a cook and a chef is understanding what's going on." - Alton Brown