These wheels use tires that inflate to an ideal pressure of 2.5 psi. (As opposed to automotive tires or most other pneumatic tires that inflate to 35 psi. or more.) The result is that these tires are so soft, they flatten soft sand and distribute their load over a wide surface. Other tires just dig ditches.
These tires also conform to irregular terrain making rolling over rocks, branches, or other obstacles quite easy.