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You need to undergo with deeper research in order for you to understand how things work and how will you take advantages with staking features of these assets. The deeper you understand, the more passive ways you can earn from those projects. It's not easy to see your investment going down but if you know that there's a good returned once the market turn to bull, instead of selling it's best to add more if you have some spare money to buy for additional coins.
More on taking your investment to a long-term goal and continue to enjoy passive earnings from your stake coins.
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.