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When adding a payment card, it is “authorized”, tested that a $5 charge would not be refused, that there is a real working card connected to banking, which can have a temporary hold on funds. However, this will be reversed out by your bank when it is not actually processed as a payment. Perhaps this is the reluctance point you encountered?

https://help.openai.com/en/articles/7438062-after-updating-my-api-payment-method-i-noticed-a-5-charge-is-this-a-temporary-hold