Why do the Eromanga dinosaurs and the Eulo Diprotodon (Megafauna) have common names like Cooper, George, Sid, Zac and Kenny?

These are identifying names we give a new important dinosaur or megafauna discovery so we know which individual we are talking about. In many cases with the dinosaurs they will be scientifically described as completely new dinosaurs and then they are given a special scientific name.  If they are not a new species then they will already have a special scientific name.  ‘Kenny’ has a scientific name already, Diprotondon optatum.