Perhaps giving free-spins/bonuses for every deposit through Lightning might encourage Bitcoiners to open a new path/method to use Bitcoin?
Just use Altcoins that has cheap fee and fast transaction confirmation like Tron, BSC and many more instead of using LN since you will still need to convert your Bitcoin to LN in able to deposit on it. Besides LN is still not popular among gamblers as an alternative to cut transaction fee compared on using altcoins.
I believe having a built-in exchange is more helpful to have a temporary solution over transaction fee since gambler can send directly Bitcoin to Casino and then just convert it to altcoin on the casino exchange to save fee for withdrawal.
I agree with, although I may say that it's a good way to promote accepting LN but not everyone are fully aware of it though. Still, I think majority will prefer using altcoins than LN ( but we never know).
I just checked my Shuffle account to see the deposit option, I see they have 11 altcoins available, so you can choose one among the many to deposit. They have USDT((I'm assuming TRC20), and other altcoins that doesn't require a high fee using their network.