Casino nowadays should really be having that standard instant withdrawal.If there are some hold ups and pendings then it would be varying into some
issues which is likely on this case.
Only few casinos have that feature of instant withdrawal and even at that it is not a guarantee for the transaction to be instant 100% all the time, since some time network congestion and other blockchain related delay may occur but at the most withdrawal shouldn't exceed few hours and if it go beyond 24 hours then it should be reported because some casino can deliberately delay withdraw processing due to their own internal errors.
*But most reputable casinos already have an established system that process transaction ASAP.