I think home field plays an advantage in that the cheering can feed a players confidence when success is achieved (long drives for TDs, sacks on third down, etc), while it can also beat down on an opponent as things dont go right (i.e., three an outs, interceptions, fumbles). If plays arent made, it's not going to make a lot of difference.
Plus you get some of mom's home cooking, relax a little more, and can sleep in your own bed.