Investing in casino tokens is similar to investing in gaming tokens like AXS, ATLAS, or ILV. They can't be considered a long term investment and is only profitable during their hype. They are also centralized so there is no guarantee that they will survive for many years and if the company owning them shuts down, the token will be abandoned and its price will definitely lose value.
Its not a matter of Centralized or Decentralized tokens, no one will be 100% guaranteed. If gamble tokens is good utility why it will not be long term? i see a few gamble platform surviving for the last few years and their tokens have good enough utilities in the market. But i'm not fan of holding gamble tokens, especially long term i will never invest.
Most of the casino projects are not listed on a popular exchanges which I don't know why. Many of the exchanges they are listed are not that known and this alone do many users to be afriad of losing there funds and coins to exchange that has no reputation. How I wish some of these casinos coins are listed on popular exchanges, that will attract more investors to keep buying.