It is unclear if OnlyFans actually accepts debit cards. Some verbiage says yes but people don’t realize they have a credit card instead of a debit. Others say no but there is no difference between a cc/dc. I assume there is a regional discrepancy there since I know europe loves debit cards. I also suspect it has more to do with the backend (? visa, mastercard, the other ones) than anything else since there is a constant war against sex workers in that regard.
At least in the US, the vast majority (I want to say “all” but) bank accounts and debit/credit cards require a parent to co-sign if you aren’t 18. I have no idea how that manfiests as providing credit card info to a website but it does mean the parents have access to the statement and will see the porn charges.