Since nobody here is an experienced money launderer, we will never know whole process. If casinos are involved in money laundering, then both casino and money owner are involved. I think they have low risk. But, I dont think that casinos are good for money laundering. How I see the process, a person place bets, losses money, then win jackpot and withdraw and the money becomes more or less clean. An accidental gambler can win that jackpot either. And that is the moment when problem starts.
Yeah, a big uncertainty in scheme to use casinos for money laundry is always exist as one may end with tainted assets that were put into casino's сleaning "drum" by others. So it may require the use of many casinos to get the positive result thus the whole procedure is not the cost effective and one lose up to 50%
or even more . Probably only hackers could treat oneself to such unalloyed luxury as to get half of their initial input.