To me, a dry brine implies a lot of salt. I think on a thin piece of meat, like ribs, a dry brine is going to pull moisture from the meat. Maybe a wet brine might somehow add moisture, but not a dry brine.
A rub, in my mind, does not have a high salt component -- probably more sugar, spices herbs. If you want a rub overnight fine. I still don't think overnight helps much because there is not a lot of penetration. But it is like many things bbq, folks have their own methods.