Yes, the fattest tyres possible are
really a necessity when you get out on the sandy tracks in the desert, believe me.
Last year a mate and I were defeated by the sands of the Andado Track. We were well and truly loaded with food and supplies for 8-10 days, and water for 2-3 days. We were running 2.3" Schwalbe Mondials and mine were down to sub-20psi to get traction, but the deep sand had us walking and pushing - extremely debilitating in this sort of soup:
We were forced to change our plans and backtrack the 4-5 days back to the highway.
Sunsets were gorgeous though