I honestly have no idea. Some people were as high as a 2nd round pick on him.
Sure, he played in a league that was below his skill level last season (D+0), but there are plenty of guys that play in that league his age or older so it's not outrageous. Loponen has played in that league this season and he's a D+2. Ffs the guy has the 2nd most goals in a season in the league ever with some random guy named Teemu Selanne being the only one to ever have more.
His path was strange, he's not the biggest guy, and besides his shot he doesnt really have any crazy standout skill. Seems like a bunch of teams (including the Leafs) kinda just said "meh" instead of seeing this insane upside.