The short answer
It can be, if you know what you are getting. Standard camps at Erg Chebbi use large canvas tents with simple beds, a shared toilet and shower block, and a communal dinner. The night sky and the dunes are the same as at a luxury camp. What varies a lot is tent condition, food, plumbing and noise.
In more detail
Our camp guide describes standard camps as the bulk of what operates at Erg Chebbi: canvas or haima tents with plain iron or wooden bed frames, basic bedding, and a shared toilet and cold-shower block for every few tents. Dinner is usually a tagine or couscous in a central tent. The experience is real, and many people remember it fondly.
The catch is consistency. Quality swings between operators, and a quiet camp can turn noisy when a large group arrives. If you book a basic camp yourself, read only recent reviews and ask how many tents there are and whether showers are hot.
Where basic camps fall short is winter. Shared bathrooms a walk away and no heating make a cold night harder. With small children, older travellers or in December and January, we would choose a camp with private bathrooms in the tent.