That's not the shot chart of someone who can only play inside. At 20-years-old, he's undeniably an offensive prodigy. Here's a taste of his abilities - a career high 31 against Dallas:
https://www.youtube.com/watch?v=nKnwVCBkeEgHe's unstoppable one-on-one and should command a double-team most times he touches the ball. That in itself is extremely valuable -- especially since Boston can surround him with shooters like IT, Bradley, Crowder, Olynyk, etc. He averaged 20 pts on 63% FG after the all star break. Again, he's 20.
There's no doubt he needs to improve his defense. He often shows little-to-no interest on that end, which is definitely disconcerting.
However, his nightmare supporting cast in Philly doesn't help. Hollis Thompson, Isaiah Canaan, Nik Stauskas, etc have no hope of containing penetration. Jah is a bit of a sitting duck there.
Boston -- with so many elite perimeter defenders -- is one of few teams who can hide him in my opinion.
If we don't land a potential star, i.e. Simmons, Ingram or Bender, we should go all in on Jah. Given we'd probably need to add a sweetener, but the deal is a no-brainer for Philly if Dunn or Murray is on the board.