How so, specifically?

His main skill is rebounding; the consensus is that rebounding is the most transferable skill from college to pro.
It's not his ONLY skill tho, as obviously he's the rare big guy who can shoot, but even MORE importantly his being outside the paint didn't affect his rebounding-- unlike say Lauri Markkanen who's 7 feet tall.
The other knock is his defense outside the paint, but I've found that kind of criticism to be faulty. For one thing, defense is VERY difficult to measure in any sport. Remember if you're a great defender (Right fielder with a cannon arm, or lockdown cornerback) it's most times intangible, due to fact offenses change their schemes away from you. But in football for instance, the world's greatest cornerback IS taking the other team's best WR away from them, so it trickles down right?

Swanigan has the best intangible, insatiable drive. You simply don't go from 400 pound 8th grader to a sophomore in competition for the Wooden Award without some serious drive. What we like best about him was his massive improvement from freshmen to sophomore year. Compare this to the crapshoot of taking freshmen who many times just had a rogue good year in college bc other coaches weren't paying much attention. Ironically, while we like Zach Collins a lot, he wasn't even starting, so REALLY a MUCH MUCH bigger chance of bust than Swanigan. It's very fun they will be competing directly for minutes with each other in Portland, and Portland has that hole in their lineup right where they both live. Hats off to Portland GM!