Why install a Intel with a IGPU when you're installing a discrete GPU?

Why do some people install an Intel with a integrated GPU and a dedicated GPU?

gives you a backup if your GPU dies ... at least you can get online and research to try and find a fix for GPU

Because the majority of consumer grade intel CPUs come with them by default. 

And, as Ratzzz said, always good to have a backup.

Thanks for the reply guys I appreciate it.