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
LN is not something that is widely used, it is a whole another place where you need to live, instead of this world, just like how we have another "chain" basically of the old bitcoin transactions when it took so much money, it is still there if anyone wants to use but then you will not be able to move your money to new bitcoin world.
Most of the new bitcoin transactions starts with 3 if I am not wrong, which was 1 back in the day, my address started with 1 for maybe 5+ years before it became 3. Same with LN, it is not there yet, it will be widely accepted when places start to widely accept it, and when every place offers that option, and people see that they are paying less than a penny and do it instantly, they will move there, who would want to stay here when that one is that cheap. However right now it is not widely adopted hence why people do not pick that.