I would personally only consider this kind of assest as a long term investment only if I had a very high trust on these casinos and their capacity to grow in a such competitive market, due to the centralization implicit on them.
The price of these tokens are tied to the success of the platform itself acting like some sort of share.
I think that for long term investment it would be better to go with a decentralized asset, like Bitcoin. I am not saying that these casino tokens cant lead to very good profits, centralized coins (like Binance's BNB) have provided a lot of money to their investors in a relatively short period of time, but these tokens are not for everyone.
True, the success of your investment depends on how the marketing will succeed to attract more gamblers to play using the casino if there's nothing that the team offers it will delay the progress in terms of value, but if there are many available feature that investors will earn the chance that it will be supported by more investors and traders.
On the other-hand, if you have a decent amount of money to invest, adding more solid asset like BTC, ETH and BNB.
It's up to you though, your money is always valued by your decision with your investment.