My understanding is that the grob is most effective in OTB games at the amateur/intermediate level, where your opponent probably has not given much thought to their responses to this opening. You can force your opponent to use up a lot of time at the beginning of the game, and if white can find a way to equalize, will have a time advantage in the end game.
I'll be curious to see how the games turn out - it does not seem to provide a solid foundation for white to control the center, and as has already been pointed out, the kingside pawn structure is irreparably weakened on the first move, meaning it's either play a "king out" style of attack or force a queenside castle.
-mike