This has probably one of the most minimalistic UI's I have ever seen for a casino website 

Think of it as a one-time faucet.

With Lightning Network, there's no need to deposit a big amount first. It (usually) takes only a few seconds to deposit, so you can do that for each bet.
You can get a balance when you win.

One of the great benefits of the Lightning Network is the transaction speed: there's no need to deposit first, as it only takes a few seconds to deposit.

Good point. I've lost all my Lighting coins there (luckily only small amounts) and I'm so used to it by now, but indeed, as a new user to a site it's not intuitive to just try to play without having a balance.

I had to check the date twice to make sure my eyes weren't playing tricks on me but I am amazed that this casino actually was based on the LN back in 2018. From what I can see how many other LN casinos has there been? I can't think of any that are active till this day. And pretty sad that there is almost no adoption to LN in the gambling community.

Like I said in another thread, I think unless there is a major reason to use a LN to send transctions most will just send BTC transactions using 1sat/byte. Currently there is little to no need since the fees are relatively low and people don't want to take the time to learn how LN works or start a channel.

I think if lightning roulette was launched sometime in the future it might of been more active then it was for the last 2 years.

That is a good and the bad thing at the moment. We all like fast transactions and no need to deposit much in.advance but thus you can easily lose control so.you might put into game more than you've actually planned.
So I still prefere more traditional ways but everyone chooses for himself.

The Lightning Network channel I have open for lightning-roulette.com 031678745383bd273b4c3dbefc8ffbf4847d85c2f62d3407c0c980430b3257c403 is still going strong and their node has a capacity of BTC 9.077 (which is quite impressive).

Hello,

What is the max bet limit?

That's bad. What if someone puts 30 Bitcoin on 0 and wins? You need to be able to pay any amount that someone can win. At most casinos, the max bet is such that a user can only win around 1% of the bankroll at a time.