Gambling is all about random number generation, and provably fair scheme provides guarantees that casino doesn't cheat, but we also know that humans are horrible random number generators - we are very easily predictable.
Not really. The gambling websites don't use the traditional random number generators. Even computers or programming languages fail at that.
So, theoretically a casino can observe how you place your bets, then predict your next bets and make their own bets (they always go first) accordingly. The flaw here is if this algorithm is implemented too naively, it can be abused by players by making big amounts of predictable low-value bets, and then making a big opposite bet.
They can predict how I bet but can they predict what's the next winning number is going to be? I think not. If any gambling site manages to do that, people would stop playing there.