I have done no wrap, wrap with butcher paper, wrap with tin foil, and the foil boat.
All methods work, but do give different benefits.
What I have noticed is the foil boat serves three unique purposes that the others do not.
The no wrap allows for continuous bark building. But you do run the risk of the flat or point not finishing the same, and could dry out the flat. You just need to either rotate to balance out the point & flat, and/or cook at lower temperatures to avoid the flat dryness.
The wrap in tin foil helps to speed up the cook, but can soften up the bark. It will help to balance out the temperature of the brisket after it pushes through the stall. And it will braise a little in the rendered fat & beef juices until probe tender. Biggest is the softening of the bark.
The wrap in butcher paper helps to avoid too much softening of the bark, allows the brisket to breathe a little. It will allow the render fat & beef juices to absorb in the paper, so no braise cooking. Also helps a little to balance out internal brisk temperature but not as well as the tin foil.
The foil boat takes a little from the other methods and combines it into one. First you continue to build bark. My opinion much needed with pellet grills vs offset smokers. Second it helps the meat side (bottom side) to stay moist because the rendered fat & beef juice are kept at the bottom allowing it to cook confit style. Third, the tin foil helps to balance out the internal brisket temperatures so the flat & point finish closer together. And one bonus is since the top is open it’s easy to probe with your instant read thermometer. Checking for probe tenderness.
But like mentioned above, all methods work well. I think it boils done to your preference of bark, and if you are using a certain type of cooker.