I don't think it matters because AFAIK most casinos value the deposit in fiat instead of crypto denomination.
Let's say you send 0.0005 Bitcoin which worth $54 (BTC $109,000) right now, after a month Bitcoin price rose to $209,000, your money in the next month would still $54 instead of 0.0005 BTC/$108.
So if gamblers gamble in this kind casino, regardless the price rise or drop, it should be same.
That’s because we are talking about the money INSIDE the casino already. The casino is not a place to hold your bitcoin and let it grow. But if you were to withdraw bitcoin from the casino, it will be worth more. The point here is that are gamblers more likely to spend when they are profiting from bitcoin? The answer is yes!