What "fair" refers to, is that you when you win you actually win, and they don't tamper with the odds. Not that they have "fair odds". That's why if you bet at 2x, you have a 49.5% chance of winning, not a 50% chance. That's how they make their money.
For those who will search or create such threads, this is the best answer to your question. Everything is mathematically simple: Casino has better chance of win and that's why you lose, haven't you ever seen 49.5 win rate? Do you think that 0.5% means nothing? Sorry but mathematically that means a lot and when you consider gambling in long run, this especially increases your chance of lose. So play for fun and not for profit.
That's a clear statement on the term provably fair used on each and every dice site in specific.
1. Everything is over mathematical scripts, in those technical aspect what we see is provably fair.
2. House edge is the next thing, very few get to win while the statement is 1% house edge.
3. Whatever might be the fact, greed is the reason for loses unlike the script being provably fair.
4. Sites give different explanation for being provably fair, we need to decide how to spend.