Could be because the bank has anti-porn terms to a card or the processor need a verification to process since anymore can use one. There so many types like vanilla visa/master or target visa/master. Have one i bought said in the back:
Not for gambling, atm, cruse line or recurring payments.
and gift card.com said their cards transactions for online gambling sites, adult websites, money transfer services, PayPal, and recurring bill payment will be declined.
I googled and some said it will work for some cards but other it will declined on others. 2009-2014 articles. This might be a jacob asking the credit processor the questions of pre paid cards and reloadables if they will work. Bank debt cards seem to be working off another users.