From what I have observed, the casino[1] that has been mentioned now currently exists in web 2.0 which is here. Eventually, they are also planning to build another version of their casino in Metaverse, particularly in Sandbox, Decentraland, and Metachance under the Ethereum blockchain

So yeah, I think the implementation of NFT in blackjack.fun would be quite cumbersome especially now that there is a pending version update on the website. It isn't a bad idea either because you see, there is a lot of space for improvements.

[1] https://luckydegens.com/