'Natural Pressures' help keep the walls together, so by simply nailing them, you're basically 'preventing' them from moving over time. Using screws is more costly although I don't think they do any better or worst than nails. You are talking about framing, right? DO realize that in different parts of the country, like Florida and California, there are BOCA Code Issues for hurricanes and earthquakes (respectively) when it comes to building homes and such. All I'm trying to say is that 1 particular home built in Florida has to meet different Building Requirements vs. the same home in CA vs. the same home in PA.
As for drywall, nailing works fine for a while until they manage to work themselves loose over time. Just last Fall, I went around the ENTIRE 1st floor, 2nd floor stairway and hallway, and 2 bedrooms adding screws where there are nails in the drywall. (I simply hammered the nails deeper and put screws above and below the existing nails.) There were nail pops EVERYWHERE! In this case, nails are cheaper than screws. As for one being better than the other, screws are by far better (and required for metal studs.)