The pallet isn't strictly necessary. After a couple days, the material is settled enough to remove the pipes and leave behind air tubes through the material, so lifting the whole thing up with a pallet lets more air through the whole thing. It probably speeds up the process a little, but it also means you have to water them a little more often as they dry out from the airflow.

A side benefit is I can put pallet forks on my tractor and move them around if necessary (though it's a little wobbly and unstable, so it has to be moved very carefully).