We are creating a financial betting dapp for TRON which is completely decentralised but in order to support non-Dapp browser users/wallets we will have a version which is semi-centralised in that you can play in your browser with altcoins too rather than the native TRC20 coin.
The idea of using of a centralized/decentralized option is completely dependent on the user and isn't related to the company which is designing the Dapp. Addition of altcoins to the platform is a good move to improve the adoption as many of the gamblers prefer altcoins over the native TRC20 coins. Though I rarely use tron based coins as majorly I gamble through bitcoin, but the robust speed of the blockchain tends to bring a lot more gamblers in future.
If decentralization tend to be on par with the centralization, the site wouldn't lose its position in the market as they would be treated upon the same for both the versions. Trust plays a major role than decentralization in terms of gambling markets and gaining trust would subsequently bring in more people towards the site.
This is true with gambling as well as with trading exchanges. Though the exchanges and gambling sites are third parties the trust gained through its legitimate service adds more people use the services. When a gambler faces an issue he/she can raise a support. The same will be attended and rectified. As in the above quote decentralization/centralized gambling sites looks similar but the trust factor is the one that brings in gamblers.