This advance is just the third most popular move. 10.Be3 and 10.Bxc6 are played in roughly equal measure.
1. d2d4  1... g8f6  2. c2c4  2... g7g6  3. b1c3  3... d7d5  4. c4d5  4... f6d5  5. e2e4  5... d5c3  6. b2c3  6... f8g7  7. g1f3  7... c7c5  8. f1b5  8... b8c6  9. e1g1  9... e8g8 