So camels take a little bit of time to get moving. The saddles are a tricky bit of machinery involving countless layers of blankets and ropes. The procedure for loading and unloading involves a great deal of balance, leverage, and stamina. And then getting everyone else together, loaded, mounted, and standing up is a whole thing. Afterwards, you can start to point everyone in the same direction and negotiate with the animals a speed everyone (including the camels) is comfortable with. And then... you are off, at your plodding speed, picking your way across the desert until the next oasis and bit of shade.