Firstly, PLEASE don't put Solana and the word "decentralized" into the same sentence. For me, a decentralized blockchain can't be turned off just because "the big guys" made a decision. The days Solana was turned off because of some error is the day that I crossed it off my list. Btw, I did use Solana once to mint some NFT shit and guess what - it was so clogged during that minting, it reminded me of Ethereum. The only difference is that Ethereum works even if it's clogged (true, transaction fees are very high at that time, but it works) and Solana didn't work.
And secondly, I'm aware what is the reason for big transaction costs. I'm just saying that currently there is not one blockchain suitable to be used in casinos to track inside transactions. We can argue which project will be first to achieve security, scalability and decentralization but that's not the point of this topic.
No. First, you don't need to use a decentralized blockchain to create a decentralized application. Secondly, if Solana has any differences in decentralization from ETH or bitcoin, then they are minimal. As for the tracking of internal transactions in the casino, why do you want to see them if we are not talking about a system of provable fair?
How would you create a decentralized application on a centralized blockchain? For example, you create decentralized application like casino on your centralized blockchain and then what? The users of that decentralized application have to trust you that you won't tamper with the transactions. What's the point of that?