Sure, but Draymond Green was supposed to be a backup too. The NBA draft is like buying scratch tickets. Even the top picks sometimes flop. A lot of lottery guys are just backups. So yeah, they are projecting guys who have some untapped potential, like Andre.
But Adama can absolutely become a starter in the NBA. A star? Probably not. He also has a high floor, he has almost no chance of being completely useless. When he came from behind to block the shot of a guard in that video, showing some elevation, quickness and timing, that should open eyes. Everybody knows what he can do on offense in the paint.