Larry covered it pretty good i think. Mainly I am speaking from the point from about 1 meter into the area of body contact range, sometimes called clinch range. Uke will not grab you "honestly" without the threat of atemi. He can stay centered and lock down on you. you will have a difficult time getting a ikkyo, nikyo, or sankyo if he can come in indiscriminately not having to worry about atemi.
However, with the presence, or hint of atemi, you can affect uke's balance/center and the dynamic changes. Some might call this KI projection