A useful move. One idea is to get his bishop back in the game after f7-f6.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1c4 No surprises so far by both players. Nakamura  sticks to his classical Black strategy, as Carlsen searches for a small  opening advantage. 3... f8c5  4. c2c3  4... g8f6  5. d2d3  5... e8g8  6. e1g1  6... d7d5  7. e4d5  7... f6d5  8. a2a4  8... c8g4  9. h2h3  9... g4h5  10. a4a5  10... d5f6  11. b2b4  11... c5d6  12. b1d2  12... a7a6  13. d2e4  13... f6e4  14. d3e4 The opening is over, and  White got his slight advantage. Albeit symmetrical, White's position is  more pleasant, thanks to his more harmonious development. Especially  impressive is his light-squared bishop, whereas the white knight also has  better perspectives on the kingside.