Earlier quoted context omitted.
Plus however long it takes to drive to u-haul, wait for them to check-out the trailer, hook it up, use it, then drive back to u-haul, return it, etc. Time is money.
Trailers should lend themselves well to the sharing economy, no? Minimal maintenance, largely stored sitting idle, no cleaning required. You don't even need to unethically deem your workers as contractors.
Trailers have a capacity advantage though. Sometimes the shit you're moving simply won't fit in a large pickup truck. In those cases though, having a truck with sufficient power to tow that trailer is still handy...