IIRC rollbit has this kind of NFT but in a form of Rollbot but the article shared on the link was NFT for the casino built on metaverse. Meaning the casino is running on blockchain which is easy them to implement NFT with benefits to its user unlike centralized casino like blackjack.fun. I think NFT idea is not easy to implement on our casino and as you said already, It really need to have proper research and devs to work on that particular area.
What blockchain is that casino built on top of? Does it function like DirectBet?
They are using Ethereum Blockchain for their NFT which is very expensive to transfer. Luckily its feature is passive and serves as a VIP pass to earn rewards while holding it. I'm not familiar with the technicality since I'm not a player but I think the decentralized casino is the same with Directbet since they are using on-chain transactions in every bet and just use a smart contract to process the result.