For shipment that are large enough to fill or nearly fill an entire shipping container, full truckloads work out cheaper.
Full truckloads are muchless encumbered by size and weight restrictions.
FTL shipments get to the destination sooner, as the truck is making no other pickups or drop-off along the way.
FTL transport means less handling (there is no transferring between trucks mid- transit) the shipment is likely to get lost or damaged.