I'll add that there are operations where items come in floorloaded in containers and may be shipped out without pallets (floor loaded or parcel shipments) therefore they don't want to invest in and handle a bunch of slave pallets. In addition, the wrapped load without the pallet may be smaller than the load on the pallet due to using standard pallets but having various sizes of loads (some smaller than a pallet) so there may be some depth and width space savings there in addition to the height savings associated with the pallet.
These operations typically floorstack most of these loads in bulk floor storage, but may also have some need for storage in selective rack.