Works perfectly as a real cooking stove. Some modern wood burning stoves are designed to work as cooking stoves. All you need is to install the cookware and adjust the temperature and you are good to go. With a good wood burning stove, you can thus reduce your expenditure on cooking gas.
Many furnaces are also equipped with glass doors that are especially necessary when the fireplace is warming up and can not deal with smoke and thus lets the bitter smell in the room. The glass cover helps to prevent it. The doors can be swinging or lifting. By the way, furnaces with a fireproof door are safer than open grates, and allow you to manage the flow of warm air much better and easier. The only drawback is that sometimes the heat-proof glass may be covered with soot.