If the casino pays the withdrawal fee, the user will thank them and that can be one of the good services to their users. But if the casino cannot give that and still applies the withdrawal fee to their users, that will not be a problem. As long as the withdrawal fee is not too high, their users will accept it.
I don't know the statistics about that but as a user, I will be happy if casino pays my withdrawal fee. That will not reduce my money and that gives more people a reason stay at the casino. Perhaps, casino representative willing to speak about it especially for those who already applied it in their casino.