I've seen a lot of gravy recipes that use butter instead of using the fat from the turkey. This seems very odd to me.
For instance, the SF Chronicle turkey article that someone posted a link to recently said that their testers liked gravy made with a butter roux better. And I think the gravy recipe in Cook's Illustrated from last year was made with butter, too. They did use turkey juices, just not the fat.
Does anyone know why butter would be better than the turkey drippings? Or is it just a way of starting the gravy in advance rather than hassling with it at the last minute?