Surrendering Center Control?

Hi folks! This is from a game I played some time ago, and in fact I posted the complete game a while back. However, while reviewing some of my past games, I've become curious about this specific point in the game:

The engine analysis for several consecutive moves keeps insisting that dxc6 is a good move for White, but to me it just looks like that surrenders control of the center.

Can anyone explain in Human terms why I should be exchanging center pawns here? Is it because Black's d and e-pawns end up weak? Is it to prevent Black from pushing pawns on the Q-side?

In the actual game, Black played cxd5 a couple moves later, and after Nxd5 my Knight dominated the board...something that can't happen if I initiate the trade.

Any thoughts?

I tend to agree with the OP. White's dxc6 looks wrong on principle.

It's tactical. Black is threatening to play cxd5 and the complications from that are pretty scary. you either take back with the knight and sac a pawn or you take with the pawn and give black a kingside attack with Nd7 and f5. And if you play Nh4 you have to be wary of tactics against that knight like Bxe4, Nxe4 Nxe4 and the h4 knight is hanging. Basically, white's center is under a lot of pressure, and you might not be able to keep it intact anyway.

Edit: It's tough to develop the dark squared bishop without giving up a pawn as well but that's a side issue because that bishop isn't in a rush to move.

I think you got it, there's more pressure on White's center than is readily apparent. The actual game continued with 1. Bg5 h6 2. Bxf6 Bxf6 3. b4 cxd5 4. Nxd5 and White's N dominates the board. But the key is that after Bg5, Black can simply steal the center with Nxd5, as the g5 Bishop is now hanging. Luckily for me, my opponent missed that tactic, and I went on to win easily.

To your second point, it's interesting that the top engine line is 1. Nh4 a6, so your Bxe4 tactic isn't recommended, even though I don't see a refutation.

Either way, this position was definitely a critical point of the game, and I gained advantage because my opponent failed to punish my error of Bg5.

It's probably because instead of Nxe4 white can play g5 but that position could be scary too after Bxc2, Qxc2 Nxd5, Nxd5 cxd5. Black gets a lot of pawns for the piece and a strong pawn mass in the center. I wouldn't mind playing black there.

Edit: This line is also more justification for starting with dxc6 because if we play the same line after, black only gets two pawns for the piece instead of 3 and the a-pawn is isolated so the pawn mass in the center might be less influential if black becomes tied down to a pawn on the side. And without the b pawn it becomes much easier for white to make a passed pawn in resulting endgames.

Thanks for the analysis and feedback. This also really answers the question of why it was flagged a such a bad move earlier in the game when I played Bc4-b3, allowing it to be traded for Black's N on a5 instead of retreating it to d3 or e2. A Bishop on d3 would provide much needed support for e4.

Black definitely had many opportunities to cause trouble in the Center or on the K-side throughout the game.