Ideally, he's a stretch 4 without the defense/rebounding limitations that the term usually implies. I don't see the tools to be anything more than a jumpshooter on offense, though. He can attack an over-enthusiastic closeout off the bounce, but other than that he lacks the quickness, footwork and balance to create his own shot consistently. Think Crowder, but at the PF position.
I like the kid. Not sure if I'd take him at 15 - more like 20 - but I like him. Most likely a bench guy, could possibly develop into a roleplaying starter on a team that needs spacing from the PF position.
EDIT: It's worth noting that his 3P% is on a small sample size. If he's really a 40+ guy from deep, he should be shooting a lot more, lol. So I wonder if any statistical noise is going on there.