Smaller and lighter hand carts like the round-handled one on the left, are made to move a small and light load of boxes. The green and larger dolly shown here is built especially to move appliances that are heavy, tall and may contain a lot of "top weight."
An appliance dolly is taller, heavier duty, comes with wrap straps and sometimes gravity conveyor wheels to aid the movement up and down stairs and other obstacles.
The bottom line is, if you're moving an appliance, use an appliance dolly!
—Whit's Appliance Repair in Bozeman, Montana