It has been explained multiple times in other threads. But. This show allows for individuals with experience - ie, back-up singers, old boy band members - to audition/compete, whereas other shows do not. This is what sets it apart from idol, x-factor, etc. different criteria/rules for competitors.
Thanks for the clarification. And I don't look at other threads pertaining to the show so this is a first for me.
Just to let you know.