Question about driving on autostick ?

So my parents got me an 06 g35 and it has the autostick with the knob and not the paddle shifters. I hate the fact its not stick and I'm not such a knowledgable guy when it comes to cars. Everytime I'm at a redlight I stick my car in neutral and if I'm on a hill and I roll back and push my gear to drive without completely stopping is that bad for my car? I never quite figured out why I can move from neutral to drive without having to press the knob button and completely stopping