A good photographer should be able to know when to use flash or when it is not suitable. Most cameras have a built in flash, but these are often restricting and only light the objects close to you.
If you can afford to purchase a flashgun, they offer so many more features and allow you to reflect the light off other surfaces such as ceilings and walls to get more natural light on a subject, rather than "hard light" from a built-in flash.   _{Your Comment}