Yes, it is an irritating part of the Casineos withdrawal policy. Why ask from player to pay the high withdrawal fees if there is an option to combine all withdrawals together and pay the single fee for batch transactions..
You can choose, want quality or quantities.
If you want a quality, the fee was based on the network condition when the fee will be always adjustable according to the current network. So when you are doing a withdrawal, your transaction can get a confirmation quickly. If you want quantities with a small fee, then do not complain when your transaction getting stuck or getting a long confirmation the worst case when bitcoin network was really high could be a few days. Can you handle that's stuck transaction without complain?
About the batch transaction, you need to wait until the minimum batch transaction happen so your transaction will be not instanly? can someone being patience waiting their tx on a waiting list. A delay 30-60 mins, I bet he already talking and complain of his transaction why not getting process just because waiting a minimum batch transaction reach.
Both of these features have advantage and disadvantage.
P.S : My last withdrawal on CASINEOS only 7K SAT and doing this because the network of bitcoin was really normal, reason why the fee increase because bitcoin on bullish moment on the market and increase the transaction of bitcoin make the network was high. If you want a low fee, then wait until bitcoin network normal again.