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.
Lightning Network is the better option, you pay less than a penny to transfer sats immediately
It's true, of course. Although, I haven't seen any significant shift in LN acceptance yet, at least as far as online casinos are concerned. Apart from BC.Game and LuckyDice / BitKong, I am not aware of any other prominent casinos that currently support LN transactions. And unfortunately, it doesn't look like this will change any time soon.
Lightning Network is not yet developed enough to adapt to online casinos. Several factors are depending on LN.
Though transactions fees are near around zero but there is a matter of opening and closing a channel between two parties you can't open/close Chanel in off-chain you must have to do that in on-chain so it is costly.
After opening a channel both parties have to deposit the same amount of bitcoins in a multi-signature wallet to make a pool, then you can exchange bitcoins for each other via off-chain from the pool without any cost. for doing this both parties have to be in online with their private keys and there is a matter of privacy. (insecure)