As long as there have been casinos, they have been used for money laundering. Criminals would enter casinos with “dirty” money (i.e. money obtained from criminal activities), convert it into casino chips, gamble for a short period of time, cash in their chips for a cheque and then the dirty money could be passed off as gambling winnings.
The explosion of remote gambling (online gambling) has opened up even more opportunities for criminals and even terrorists to launder money. Organised crime is nothing if not opportunistic and so the possibilities offered by online gambling to offenders has been grasped with both hands.