It is important to use the right oil and or butter for sautéing. When cooking with butter, it requires less heat (you don't want to burn it) than other oils in order to fully cook, while olive oil requires more heat you can typically brown them better than with butter. Butter is a great choice if the ingredients are sautéed in small batches and served immediately after cooking. On the other hand, olive oil is a great choice for cooking food in larger quantities. Sometimes I will combine both, butter and olive oil.