I think the drunk animations are just a NPC animation, sorry me laddo.
I think you're right. I would guess that the drunk animations are NPC only, kind of like the smoking animations in Fallout 3. Most likely, drinking alcohol will have a similar effect to Fallout 3, and I'm not sure what that is since I generally didn't bother with it. Except that maybe it will effect dehydration in hardcoe mode.