The great advantage of foil is that it makes it a little more predictable how long the meat will take to cook. With practice is also makes a more predictable product easier to achieve. It is a valid tool if you are cooking just a few chunks of meat.
I use Heavy Duty foil, as wide as I can get. I generally will put a pan under it to move it around, as the bone easily punctures the foil. I vent the foil a little, a couple of holes, but, that is not necessary.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"I'm Armenian...perhaps...but then again...maybe not..."