This is sometimes referred to as Desert Pavement.
The small rocks are embedded in the dirt and pretty much stay in place
making for a fairly flat and smooth surface.
It is nice to camp on as there's virtually no dust and you're not tracking dirt inside.
Last night I learned another nice feature of desert pavement while cooking my dinner outside.
When you pan slips off your camp stove and the chicken hits the ground its no problem since there's no dirt. Yep, last night's dinner was fortified with extra minerals.