The word 'Desert' would not encompass all types of desert surface.
Both are images of the Thar Desert.
The surface is different.
There are two types of surface basically - the hard and the soft.
In the soft sands even 4 x 4 vehicles get stuck.
That is why if one has noticed carefully, some trucks have winches in front on top of the bumper to pull out vehicles that are stuck. Most of these vehicles are with the Artillery.
The basic cargo version is also used as an artillery tractor for calibers up to 152 mm. Most versions carry a self-recovery winch and add-on extras include snow ploughs and a dozer blade for clearing obstacles. One special engineer version carries a large crane and a dozer blade. A tyre pressure regulation system may be fitted. The Tatra T815 has been exported and the 6x6 version is license-produced in India; the 8x8 version is used by the Indian Army.
Motor Cycles are not used in the deserts since they cannot move as is expected.
MC are used as Despatch Riders. There are other subsidiary use also such as sheparding convoys etc.