Their services are usually cheaper. Do not assume that the Chinese are giving you anything free. These cost less than hotel restaurants and some are clean. One backpacker spent two and a half months eating cheaply at market stalls and never got sick. But others aren't so lucky, so stick to well-cooked food and avoid tap water and raw vegetables.
China has a lot of food stores now with cheap, decent looking cooked foods on sale.
I've taken paper bowls to China to be filled at street markets. Travel with Chinese friends. Avoid tourist restaurants. Travel during low tourist season. The south is pleasant in the wintertime.