Hayne has potential, there was a couple times where he beat 2 - 3 players in a row with ease. He's just still getting used to the rules and hasn't had much game time. Ben Ryan did say before the tournament he was only going to bring Hayne on in the last 2 minutes of each game, so I guess Ryan's intending on developing him over the next few months and this is just a little intro for him. Hayne clearly doesn't understand the rules at the ruck, he got penalized twice in a row against Australia for not releasing before going for the ball. He looked totally confused when he was penalized lol.
It will be very hard for him to make this team, Fiji still have the likes of Tuisova, Rawaca, Ravouvou, Nakarawa, Kunatani and Pio Tuwai to bring back into the team. And even then there are other players who have played for Fiji this year that will be trying to get into the team as well. Once he learns the rules at the breakdown properly and gets his fitness up he will be very good though. It looks like he has no problems beating defenders, he's just barely had the ball.
Edit: Jarryd must be too used to the NFL size ball, he's dropped the ball quite a few times and been slipping over a lot too