Bottles up the black pieces a bit by closing the diagonal of the light bishop. Perhaps Bf5 first?
7. O-O Nb8d7 8. Rf1e1
Redundant as there are officers yet to develop and the f-file is half open already, leading to the traditionally vulnerable f7 pawn?
8... Bf8e7 9. Nf3e5
lets black catch up by exchange or if refusing that, win a tempo with Ng6.
9... Nd7xe5 10. dxe5
a blocked and isolated though center pawn. Threatens the knight but it has a perfect place to go to.
10... Nf6d5 11. Bc1d2
an exchange would block the d-file, and black could claim the half-open c-file. This permits Qb6+ and then Qxb2. Qf3 looks more promising?
11... b5
Overlooked Qb6+, catches up on pace instead with tempo moves, making space on the queen side.
12. Bc4d3 Qd8b6 13. Kg1h1 Bc8b7 14. Qd1f3 c5
? Prepares Nxc3 with a threat on the queen as well as opening the diagonal towards the white queen, but the diagonal can be blocked with Be4, and the defense on b5 is insufficient.
15. Bd3xb5 Ke8f8
Kd8 would put the king in the crosshairs after Rad1. Protects the undefended g-pawn too.
