Any scheme is great when it works and based on the Giants' regular season record, the Gilbride offensive scheme works about 50% of the times. Arguably, the percentage is the same, or even less, during the playoff; the only game where it really worked was during the Packers game. In the other games the Giants offense may have had the same passing yards; however, it did not reflect in the final score. And that's all that matters at the end of the game...
Any "pass happy" offense will struggle against teams with good defenses; the niners have certainly been one such team, but statistically the Falcons defense was more of a problem for Eli and company. During the regular season the "not so good" 'skins proved to be a lot of problems for Eli and company; mid-200s passing, four picks, and lost both games. While the regular season does not matter now, you can bet your dupa that Belichick had analyzed these games and will use some of the scheme from these 'skins and other games. He can analyze these games as much as he wants to; if he doesn't have the players to stop Eli and company, then sayonara...
The resurgence of Giants defense during the playoff was probably more of a reason than the offense that they've reached the Super Bowl. If the defense performs in similar manner, then Brady and company will be in trouble.
GO GIANTS!!!