They don't have access to your credit card or banking info for this. They have their own debit card that you can purchase and that is the only card involved. This new auto top-up feature can only happen when you manually send cryptocurrencies such as Bitcoin to your Crypto.com wallet. The $500 limit keeps things from getting out of control because one you top-up your debit card, you cannot undo that process and the money must be spent. This may not be for everyone, but it's convenient for me as I have been using my Indigo debit card for almost a year now.