Some casinos signature campaign payment policy is that they would pay signature campaign participants directly to their casino account. Maybe that is a way to reduce the stress of paying for transaction fees and all of that.
Before one applies for such campaign, it is clearly stated on the terms and conditions to accept before applying for such a campaign and mind you some casinos do have standing policy with respect to wager and minimum withdrawal and in some cases they give participants free will to withdraw but from OP point of view here, I don't think payment to casino account would turn one a gambler depending on the casino withdrawal policy and if it requires that you gamble before you withdraw then you will have to do it because you saw, read and accepted the terms and conditions before applying for the campaign
However, if the casino give a special preference to campaign participants to withdraw without any commitment since they work to get paid for it then it is fine otherwise one would need to gamble so as to meet the requirements before they withdraw.