Payment processing fees can adversely affect the profitability of online casinos by diminishing their margins on player transactions. As these fees accumulate from high volumes of deposits and withdrawals, they can significantly reduce net revenue, especially if casinos absorb the costs to maintain customer goodwill. Alternately, passing these fees onto players may lead to dissatisfaction, potentially harming player retention and overall revenue. Consequently, effectively managing these fees is essential for online casinos to preserve their profit margins and remain competitive in the market.