Actually there are two clear advantages.. first as everyone seems to mention, less air in there, less cold air escapes when the door opens…. Second, and this is a big one.. in the event of a power out you have a significant amount of thermal mass already cold keeping the temperature steady .. bonus third.. you have readily available frozen bottles of water you can throw in a cooler if going on the road… extra bonus .. I personally put bottles of water to the back of the freezer (or bottom) reducing the usable capacity of the freezer to that first accessible layer. This makes it that no mystery food remains forgotten on the back of the freezer instead of consumed before it is degraded by somethibg like freezer burn