@OP: As far as I know there is not a decentralized casino yet.
But there are plans like
Pangea project of SuperNET which aims to create decentralized poker on the blockchain. Recently I read about that there are also plans to create decentralized dice games ( could not find the source ). Projects like
IOTA for instance, which do not charge any fees and which allow to send thousands of transactions per second, can be a good foundation to create real-time decentralized casinos.
Is there a single decentralized casino project with active users? These were projects where supposedly no one holds the funds in one huge pile, or something similar.
Are the "real ones" still clearly better?
Never heard of that concept. Does it work like an exchange? How is a payout guaranteed for those big wins. Also I don't know how that works if there are few players in the casino, thus low funds.