It is hard to answer accurately to this question without knowing more about the actual type of simulator and the goals of the person using it. There are many different models of simulators on the market, ranging from the cheap computer games for $50 all the way up to Full Flight Simulator with the price tag of over $10,000,000.
The main purpose of high-end plane replicas is education and training. Cheaper software applications and aviation games where primarily developed for gaming industry but also have high educational values. Some models of flight simulation games are developed to very high standards and lot of flying schools are using them to train their novice pilots and flight crew. This way the costs of training are reduced significantly and the safety and security of pilots is raised to a much higher level. Such software applications are ideal for practicing various maneuvers and procedures without risking the life of people.
With the recent advances in computer technology and graphic we have also seen huge improvements in development of flight simulation games. Lot of flying enthusiasts and aspiring pilots now have the opportunity to experience realistic flying and learn lots of fundamentals and theory before deciding if they really want to peruse the career of a pro pilot.
As already mentioned, the level of training will depend on your intentions and the type of simulator you use. In general, simulators can be used for anything in aviation that comes in mind. Aircraft, landscapes and runways can be redesigned and changed to match the needs of our training program. That is especially true in military and aviation industry where changes in climate and weather conditions are of ultimate importance. It's vital for a pilot to get familiar with all different types of scenarios and failures as if such situation later arises in a real life he would know how to respond.