In the following line of the Polerio defense, black has an advantage close to -2 according to the engine:
[FEN ""] 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 Na5 6. Bb3 Nxb3 7. axb3 h6 8. Nf3 e4 9. Qe2 Be7 10. Ne5 O-O 11. d4 exd3 12. Qxd3 Qxd5 13. Qxd5 Nxd5 14. O-O
I tried it out against an engine but kept making moves that equalised, because I really don't understand what black has here, or what I should be playing for with the black pieces. Obviously I see that I have better development and a maybe slightly better pawn structure, but I don't see how that translates into a coherent plan where black has the better chances.
Is the idea here simply that black has the bishop pair and a slightly better pawn structure and therefore should win the endgame after enough trades?