What I noticed is that the minimum withdrawal amount goes up with the bitcoin price but never really goes down anymore. We are 50%below the ATH and it doesn't seem like the next rally will come any time soon, maybe it would be better for casinos to change their requirements again.
In stake, I've noticed the adjustment of the withdrawal when bitcoin's price has been up and that's what I think the same for the other casinos. But if they happen to have some fixed amount for minimum withdrawal, I think you can demand that to where you've been gambling with and ask them to lower the minimum amount since the price of bitcoin has been up. But just as what I'm thinking, the price went half from the all-time high and they can adjust it without any demand from their players to have it raise again or just stay to the fixed amount that they've been doing all of this time.
For me it is better to gamble with bitcoins when the volatility is lower. When there are no big price jumps it's easier to leave some coins at the casino.
The volatility of bitcoin won't change but sometimes it becomes stable and if you're fine with that price and the current fee it shows, that's the right time for you to transfer or deposit.