Interestingly, Noren also uses a massive forward press on his full swing, so he obviously feels comfortable holding golf clubs with his hands well ahead of the ball.
One of the advantages of putting with a big forward press is that it makes it easier to generate topspin when putting. This helps to keep the ball rolling end-over-end, which encourages the ball to stay on the intended line (when executed correctly).
That being said, when you employ a big forward press with your putting stroke, you effectively deloft the putter face. This can have a negative impact on how the ball launches off the putter face.
Most putters offer about 3 degrees of loft, to encourage a very slight launch that helps to get the ball rolling and moving in the right direction.
Ideally, if you use a forward press, you should actually increase the loft of your putter.
This might explain why Noren keeps the putter face so open at address. Opening the face increases the loft of the putter, which counteracts the delofting that occurs with a forward press.