I don't wrap during the cook, and I cook at a fairly high temp (275) which tends towards hard bark. But I wrap in plastic wrap for the resting period which softens it slightly, but sometimes it stays too chewy. You can probably get better bark with a slower cook (225ish) a little less rub, and a loose foil wrap during the rest; but you lose predictability in time through stall, as well as four hours or so towards the project. That's prep, chamber, and/or sleep time that could be more profitably employed. You might get a little bit better smoke penetration (and ring!) at the lower temp, but you get a more even and juicier cook at 275. And so on.
Like so many other things in life, choosing methods means managing trade-offs.
What were we talking about?
Klose Steak Grill with Swing Set
Backwoods Fatboy with DigiQ II