Protects the e-pawn should White decide to exchange on c6, but, yes, not a convenient place for the bishop. 3...d6 (Steinitz Defence) was possible, but more usual is 3...a6, after which Black plays the usual 4....Nf6 or the Modern Steinitz (a favorite of mine) 4...d6. Another favorite of mine is to play 3...f5!? (Schliemann) a highly tactical and combative line.

Bad move. You are giving away the bishop pair (0.5 pawns) and development tempo (c8-bishop is now freed) (1 tempo, 0.3 pawn) for a structural advantage worth less than a quarter of a pawn. Guideline: 3 tempos = 1 pawn.

I don't agree that this is a bad move in principle - after all after 3...a6, 4.Bxc6 (Exchange Variation) is a very playable line. But here's a thing. The exchange in this position has the effect of turning 3...Bd6 from a mediocre move into a very good and thematic one after 4...dxc6.

I think I prefer the pawn move, in the light of 6...Nf6 7.e5!

I missed e5.

Good

Offering to exchange Queens. I think I would prefer 7...Bg4, here, even though there is no pin.

Black ought not to push so hard for the Queen exchange - it is costing time.

Here 10...Bd6 was worth a look...