Look, the violence, tobacco use and mild swearing are NOT why I believe this game isn't really for kids. Its the themes explored in the game that make me pause whenever I see someone saying how the game isn't really inappropriate. No, the level of violence might not bother some people at all, even if it does get quite bloody with the melee executions at times. This game deals heavily with things like racism, religion and political extremism. If that's not too bad, should you want to play the "Burial at Sea" DLC, it gets much MUCH darker, including a chilling torture session of the POV character that actually gave me nightmares! (At 18 years old). Aside from that the plot can be a little confusing occasionally, though it is excellently written.
The story and characters are masterfully presented, the gameplay is excellent, and this is, hands down, one of my favorite games. I believe a parent and a child could learn a lot by discussing some of the things that happen, but only if the child is mature enough to understand what's going on and why. Also Burial at Sea was downright terrifying at some moments. A mature teen should handle it fine, but proceed with caution. Blood and gore are not the only things that can give you nightmares.