It has significant surprise value. Fischer used it to take down Spassky in 1972 WC match. Some lines similar to Sicilian, again playing ...c5 on move one. Be aware this opening is super tactical, so suggest you check some lines if you decide to play it.
also an idea is to push p on the queenside, like: a6, b5 exetra rook b8 if needed. and there is a game of michael tal and he also played Bd7 to prepare b5
Man, I play Old Benoni OTB and I play it with d6 so it's not the Modern Benoni style but first I go Nf6. So after the first move they are extremely confused, even more after Nf6, when they play c4 they have no idea what is happening when I get to Benko gambit and when they try to decline it with Nc3 I play e6 with Blumenfeld so they faint
It doesn't really allow your opponents into those openings because of the immediate c5 (which is why it may be good against d4 players hoping to get a solid set-up that they are used to) I suppose they could continue on with their London or queen's gambit-ish set-up but you can just take the d pawn and trade a wing pawn for a centre pawn (I don't know the actual theory other or what the best move is but that is generally considered good)
It's completely ineffective because white's second move is just to cover the queen pawn with one of the pawn's next to it. You don't have to advance or take at all as white Then you play the London as normal.
Against queens gambit you just take the d pawn and it's a winning position for black since white can't play knight c3 Against london system you also take the d pawn and mess up their pawn structure, so they can't really build a strong center
Dude what if they defend with the c pawn? when i'm playing white and I face the Old Benoni I usually crush the person that is using it. Do not use this opening.
That is objectively worse than pushing. If you crush opponents like that it's because they play poorly not because defending with the c pawn is strong.
