Baking and Roasting: what's the diff?

In frying, the fat doesn’t boil, the moisture in the food turns to steam and escapes from the food, causing the appearance of boiling. Under pressure, the moisture in the food doesn’t turn to steam until a higher temperature is reached, so the meat retains more moisture, and tastes juicier.

Ahh… I see, now I can see the point of it.