Why do dry brine recipes require turkey to be bagged when it's also recommended for the turkey to sit in fridge uncovered to achieve crispy skin?

Though I am a month late, thanks to each of you for taking the time to answer my question. Much appreciated.

Dry brining causes a lot of liquid to be formed on the surface of the turkey during the resting period - you don't want this dripping in the fridge.. Bagging also allows the liquid to be reabsorbed to some degree. After brining the turkey should be wiped off and allowed to air dry in order to get the crispy skin..If you start off at a high heat (and then lower it) the skin will dry and brown nicely.

There's no particular reason a dry-brined bird has to be bagged. The technique works fine if the bird just sits on a plate. Uncovering it for last twelve hours or so in the fridge, after patting the skin thoroughly dry, will help further dry out the skin, encouraging browning without greatly affecting the salt's ability to permeate the meat.

I would recommend keeping the turkey bagged to achieve best results when brining. You will still be able to achieve a crispy skin in the baking process.