The general feeling of all these high heat methods is the high heat seals the outside of the meat, and while it cooks less moisture escapes from the inside of the meat, leaving it much more moist and flavorful.

I know when I cook a roast over an open fire it's a billion times better then cooked in the oven or coals. It's crusty on the outside, tender and moist and juicy inside, and picks up some of the smoky flavor from the coals. I assume it would be the same with a turkey.

Ovens are great for cakes, but most meats do much better over a fire or coals or something.