There is also the juice factor.
In foil the juices from the meat are contained for later use, as in au jus.
In paper, unless you put it on a rack in a foil pan, you will lose a good part of your juices into the fire.
I foil and use butchers paper, depending on how I want the brisket to turn out.
I also go nekked with nothin on the brisket as well.