I don't think he has been outside at the three "so often" but the fact is this team is going to need to shoot threes a lot to compete, IMO. We don't have players who can really reliably go to the rim or create for others right now so we have to space the floor very well.
Also, a three pointer would be a good addition to Sully's game. He has a mechanically sound shot. In a year where virtually nothing is on the line, I don't mind him working on that in game.
I've always thought if all goes well Sully could be Kevin Love-esque. And part of that package is obviously three point shooting. In my eyes, nothing to be critical of right now.