Think of it this way:
If the school you're applying to has, say, 100 seats. On Dec. 1st, they give out 75 acceptances to all their pre-Dec interviewees. Suddenly, you have cut your chances by 75%, and the AdCom is going to be much more selective with who they pick to fill those last 25 seats, so your chances get even worse. Of course, if you're a 3.9/25AA kind of person, it likely won't matter, bust some food for thought.