As of now, it is best to avoid using Roobet's withdrawal feature until charges are taken into consideration.
If players want to use Roobet as a casino where they play, then of course they use the withdrawal feature, especially if they can make their balance increase because of winning, if withdrawal fees are an obstacle then you can choose LTC as a deposit option so you can make withdrawals with LTC, since the fee cheap compared to BTC or ETH and ETH is lower than BTC, however lowering the BTC withdrawal fee is sure to be greatly appreciated and pleasant thing for players with low balance like me.
^ According to the thread created by @Pmalek regarding the withdrawal,
https://bitcointalk.org/index.php?topic=5333602.0.
Even you will sue the ETH, BTC, or LTC, the withdrawal fee was still the same, it is I think ranging from 6-8$ while BTC is on $10 which is still good enough. I think even you will choose LTC still you will charge a dollar rate of LTC, ETH, and BTC. Nevertheless, you will really annoy knowing the fact they had a fixed transaction fee upon withdrawal. Imagine, the BTC fee as of now is 1 sat in the mempool but still you will charge yourself worth $10 for the fee. So definitely, it is good to hear if they will accept Lightning network as a payment method.