Possibly Kabbi only seems to score from the bench because he never starts! I'd give him a full game.
He has started in some games and has not made much of an impact, and sort of lost his way a bit.
I think he is much better to come on off the bench, no defence likes his pace and trickery in the latter stages of a game.
I would think teams set up to neutralise him when he starts a game, and I don't think Kabi has not yet got the craft and experience to thwart their attempts, but that will come in time.