@Le Happy Merchant:
I thought the same myself, but I won 5BTC so I can't complain

And yes I agree it looks fishy/like a scam. He should give his players insight into the lottery to get them more confident.
BUT, I'm sure nearly any casino got something fishy about it, and if you got a problem with that, DO NOT GAMBLE!
I won 5BTC, so I can tell you it works, if there actually is a jackpot of 10kBTC, I don't know!