The theory hinges on the idea that SDA is underdeveloped and given his age his stats should be treated as a D -1 player. In that case he would be a first round pick in 2019.
It's a reach. He needs to add about 20 lbs of pure muscle. Realistically he has maybe a 10% chance of playing in the NHL.
Personally I think there were better options on the table at 76 such as Lauko, Ranta, McLaughlin, Shafigullin and Dostal.
There's plenty of upside with SDP though, we made 9 picks and we took some safer guys so if Dubas wants to take a major cut, low chance of working out risk in the 3rd its probably worth a shot