Actually the more likely scenario as that of mixing stolen BTC.  It's a pretty well known fact (provable with the BTC ledger) that FBC is used as sort of a mixer for those that like to play with other people's BTC.  They dont care if they win or lose so long as they get back mixed BTC.  Anonymous casinos are just one of a plethora of options for mixing BTC,  its mostly just personal preference on which options a hacker will use.  Some use multiple options, others dont.  The end result is still the same.  Mixed BTC.  Note that it's MIXED and not "cleaned" BTC.  There is no such thing as "cleaned" BTC since it's not a privacy coin like Monero.  The idea is to mix BTC so much with "clean" BTC that by the time someone tries to block or blacklist it (if its consolidated into a single or only a few addresses),  it's to late and would affect others who had nothing to do with the theft to begin with (including themselves).