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.
I also don't like the Lightning Network because I have never used it at all in addition to the fact that the lightning network is still not popular with many people and it may be true what is said above, honestly now altcoins are an alternative where they can choose more simply in small and cheap transactions.
I have also deposited Bitcoin into shuffle with a fee of $8 which is heavy for me but because it was free BTC that I got so I decided to deposit there.
But the best choice is TRON including USDT TRC20 with a fee of $1 from exchange withdrawal to Shuffle.
For me that's really the coin that is very suitable for gambling, not only it's transaction fee is cheap and fast to confirm, you can also make sure that you won't be affected by crypto price volatility. That way, you'll be able to focus on winning alone and will not have to worry if the value of your currency will drop over time. Liquidity wise, it's easy to trade this coin as most of the major exchanges have a decent volume on USDT TR20 if traded with other coin.