Would animals like camels and horses be more useful/practical in the deep desert than vehicles like dune buggies and sandrails?
Basically, I have a planet that's mostly desert surrounded with rock formations and steppes. The deeper you go into the desert, the higher the dunes are, with the deepest places having straight up walls of sand that travellers have to go around. 1000-foot-high sand mountains are not uncommon.
The people there use sandrails/buggies to travel around the less steep, more inhabited areas; but in the deep desert where the dunes are highest and there is no water, would it be better to use a camel-like animal for transportation? I imagine it could carry more supplies than the small sand buggies, and you could line a bunch of them up together to make a caravan. They could also navigate the terrain more easily.
All this assuming travel speed/time isn't a problem, of course. The people's technology level in regards to vehicles is similar to ours.