Birth control sugar pills

Hi can someone please explain the purpose of the birth control sugar pills? I read online that while you're taking them that's when your period should start but I started taking them the first day of my period so according to the app I shouldn't start my period for another 6 days and by then I am starting a new pack of birth control pills. So what is the point of the sugar pills, and why don't they just give you a pack of active pills everyone?