I don't see how the 51% attack and Proof of Work and miner reward examples are relevant here, you are talking about Bitcoin casinos vs Traditional casinos but not about Bitcoin blockchain. Even if a transaction cannot be stolen once broadcasted, it doesn't mean that a cryptocurrency casino cannot scam you, and that is what we should be discussing. A transaction made with a bank card can also not be stolen once generated which you do in traditional online casinos, so I don't really see that as an advantage or a disadvantage.
What is actually an advantage that you could say is the deposit and withdrawal times, which can take days, especially withdrawals, if you are using a traditional online casino while it takes about minutes or sometimes hours for a cryptocurrency withdrawal to reach your wallet from the casino.
In fact, there are quite a few parameters for financial flows and transactions using cryptocurrencies in a casino that allows players to play with a deposit in cryptocurrencies. I will list the main ones.
These are: the requirements for the cryptocurrency itself, which coins can be used in this casino.
These are the minimum and maximum deposit requirements.
These are the requirements for the minimum and maximum bets in the game.
This is the wagering requirement required to withdraw funds from the deposit, which is also indicated in the TOS.
This is an additional commission set by the casino for the withdrawal of cryptocurrency from your deposit in addition to the net commission of the network of this cryptocurrency.
Finally, this is the requirement to pass or not pass KYC when withdrawing money from the casino. There may be other requirements as well.
And all of them are important for the player.
So in any case, you should carefully read the TOS before starting to play in a new crypto-casino.