You are correct, but we (providers) are seeing this also with P411 and tryst, to name a few. The CC companies are not allowing processing for pretty much any adult content sites. Most of the sites are going to payment with bitcoin. SESTA/FOSTA biting everyone in the ass again for "sex trafficking".

There must be a lot of rules and regs regarding financial institutions (banks, CC processing companies) and "vendors" or whatever category Gift Card monetizers (or Frequent Flyer Mile monetizers, etc.) are in and what they MAY do and what they MUST do.
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The following are GUESSES on my part, but if you know the R&Rs more precisely, please chime in. CC companies have R&Rs regarding payments to foreign parties. Some of those R&Rs resulted from Homeland Security stuff in order to cut down on financing terrorists (not to be confused with TERorists) and int'l criminals. I am guessing that the CC company has a certain amount of time to verify a payee or reject the transaction outright. They might also be looking for the frequency of customer complaints and demands for refunds. If they think they will have trouble collecting PAYMENT (from the payer) that might slow things down ... to the R&R time limit.  
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The GC monetizer companies might first scan lists of stolen GC serial numbers to reject a submitted GC outright. That should take 2 seconds or less. Then, they are probably looking to confirm that the GC has cash value and that the monetizer can securely claim and control it before anyone else can snatch it. Once they have the CASH (electronic cash equivalent) they can transfer a portion of that to the payee (as long it passes the Homeland Security and other R&Rs). I am guessing that their customer rules are not as consumer-friendly as CCs. "You hit the [Pay] button. We paid. There is no [Undo] button. No backsies. You want to play games with your payment? Use a CC instead of a GC. ... NEXT!"  
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Domestically, I have sometimes returned an item for a refund. I am always told (by the vendor, not the CC company) that, "it may take up to 3 biz days for the credit to show up on your CC." It is almost always FASTER than 3 days.
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http://capitaloneshopping.com/research/number-of-credit-card-transactions/
The world’s three (3) largest credit card processors facilitate over 600 billion transactions per year.
o The total number of transactions Visa processed reached 192.53 billion in their FY ending 2022.
o UnionPay processed an estimated 279 billion global transactions in 2022.
o Mastercard processed an estimated 164 billion transactions in 2022.
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(Smaller companies, like Stripe, Helcim, Square, Paypal, etc., are intermediaries that provide CC processing for merchants and other vendors (Uber, doctor's office, ...) . Do Stripe et al. process transactions DIRECTLY between the customer and the CC company account or do they just send their transactions through the Big Three?)