The bishop gets out first
Develop the light-squared bishop before you shut it in.
After 2. 3. your d5 pawn is fixed, and later you will need to support it and develop your kingside. But as soon as you play , your light-squared bishop is shut in behind its own pawns. That is why it comes out first: places it actively outside the pawn chain, and only then comes . If White chases it with , the bishop finds another square on the same diagonal and stays outside the chain.
8 in 10 masters choose it here.See dataHide
Over-the-board games, 2300+: 76% of 1,998. Online, 2200+: 67% of 5,643.