At first, this is a strange opening because in the Grunfeld I would want to play c5 and in the Slav I normally wouldn't play g6, but it seems very solid and it works against all major non-e4 openings.

After searching my database of 2600+ players, I found only one four move agreed draw between Kasparov and Smyslov. It's clear that  this is not a fashionable line at the top level. However, after looking at the theory with Bd3, Be2 and Qb3, I still haven't a clue as to how I can press for a real advantage. White is a bit better but Black is just so solid that I wouldn't know how to get anything out of these tiny advantages. To get to the point, what is the status of this opening and why is it so rare? Do any of you have experience with it?