Camping in the desert can certainly make your pack lighter. Think of all the things you get to leave behind: fishing gear, bug repellent, water filtration gear, bear canister. And you might not even need a tent. That's more than a few ounces--it might even be a few pounds!
And then you remember that you will also have to carry all of your water--a gallon a day per person, at the very minimum. And it doesn't see like such a good deal after all.
Not shown: pack with many water bottles in it.