.

Why give black counter-play? At first glance it looks somewhat weakening for white's queenside pawns and of course, white's bishop is dark squared. Looks too much like a pointless shot.

I looked at one of the games and the 2500 rated white player didn't play well and lost. I think white needs to clamp on e5 and try to win an endgame. What other serious winning strategy does he have, apart from hoping for blunders in some sort of kingside pressure? Ideally he should try to combine the two approaches if possible. Playing b4 just doesn't fit in with this; it's too early and he wants to create medium term kingside pressure and long term queenside pressure. b3 is alright, because it protects the queenside majority.

 White's a-b pawn duo is an endgame advantage and black's a and c pawns are both weak. Win either Black's a or c pawn and White would have winning chances in an ending.  b4?! blows this up. It is answered a5 and now Black will liquidate his weak a-pawn  and create an isolated pawn of White's permanently in need of defense. I see b4 as a strategic blunder and I'm a looong way from IM! or even M for that matter.   

White needs to clamp on the centre, which is e5 in this case, and to ensure mobility for his bishop. His winning idea is pushing the a and b pawns at the right time. Pushing b4 too soon gives black a target. On balance there's probably nothing to be gained in clamping down on black's d6-d5 because white's game becomes passive. Therefore I think an early b4 is positionally unsound and that grandmasters would easily recognise this.