I think it can only really teach you how to shift your gears, if you are driving on manual and own a gear shaft controller. The acceleration, steering and breaking usually do not really resemble real life driving at all.
Somebody told me a long time ago the first GTA helped them pass their drivers test. I took that statement with a grain of salt.
No racing game is going to help someone learn how to drive. If a person even thinks that's true, then I don't want to be anywhere near them on the roadways.
You never know which one of these people have learnt driving from racing games. Real diving is a whole different ball game if you ask me.
You're all looking in the wrong places. Look at Project CARS on the PC. That's a game that definitely can teach you. So stop talking about GTA or anything, that will never help you do anything IRL.
Racing games have helped me. I race with a clutch on forza and when I went to drive a real manual car it was like second nature. Still I needed to get a feel for a real car because it is not just some buttons you can press to drive it. I would say that racing games helped me understand how the car was actually going to be.
I think racing games mostly help with awareness. You can't really drive the same in reality though because it becomes a lot more dangerous to do the things you do. It can teach you a little about breaking and corners too though.