The tactical pawn advance to d6 is characteristic of White’s strategy in many variations of the Benoni Defense. Pawn to d6 clears d5 for occupation by a Knight or Queen, and in the chess position you see below is good for a crucial tempo against the exposed Black Queen.
Two exchanges at e5 produces a passed d pawn which White plays to d6 attacking Queen at c7. This wins in a complicated variation that human beings would not discover. In this blitz game played at the ICC, white did not find the complicated line mentioned above. One of the benefits of playing chess at the Internet Chess Club is one gets much more practice in noticing and using sharp tactical motifs. Hopefully, ones over the board USCF tournament play will benefit from seeing and playing enough of these ultra sharp tactical themes at the ICC.
The pawn move d6 is an example of a clearance move in chess. Often a pawn will sacrificially advance in order to clear a square for occupation by a more important piece. In this case, clearing d5 was more important than worrying about whether the d6 pawn was ultimately lost.