In a vacuum, this is a fun pick for the 76ers. They could use shooting and creation around Tyrese Maxey and Joel Embiid, and McCain definitely provides the former and could supply some of the latter.
But if Philly wanted a net-shredder, why not go with the plug-and-play Dalton Knecht here instead? This feels like an upside play from a team that should be operating in championship-or-bust mode.
As for the prospect the Sixers actually drafted, McCain is a master shotmaker—all manners of looks, all areas on the court. During his lone season with the Blue Devils, the 6'2" scoring guard converted 52.1 percent of his twos, 41.4 percent of his threes and 88.5 percent of his foul shots.
He doesn't have much size (6'2", 203 lbs) or elite athleticism, though, so creating separation could be a challenge for him. Ditto for finishing at the basket. Teams will go at him defensively as well, and while he competes on that end, he'll be physically outmatched more often than not, especially if he's playing at off-guard.