The only thing you earn from completing a raid/ROC/mission is the chance to be lucky enough for RNG to bless you. It doesn't matter how many times you do it or how hard it was, that chance is the only thing you earn. You know you are going to get 9 coins at the end of a level 30 weekly heroic each week and that's what you are working for. No mysteries, no praying at the screen with your fingers crossed watching that square spin in anticipation. You go in because you want the coins and when you finish, that's what you get. So what is exactly earned here?