&gt; The credit part is necessary because until recently, the technology simply didn&#x27;t allow for online processing of payments, all the way from the debitors bank account. The payment would clear against your credit, the expectation that you&#x27;re good for it, not actual cash in your account.<p>Nope, that&#x27;s not at all how MasterCard&#x2F;VISA debit cards work. They are not processed online, you just have an online authorisation.<p>&gt; Running such a network is complicated, thus the fees.<p>Except the fees go to the issuers and not the network.<p>&gt; In the past 5 or so years, both Visa and MasterCard have introduced proper debit cards, that is, card where payments are instantly processed against your bank account balance. This is still complicated, but essentially a new, much simpler and more modern network, and thus fees are much lower.<p>Nope, MasterCard&#x2F;VISA debit cards work just the same way and are processed the same way as credit cards. The only difference is that the issuers charges the card holder later and allows him to overdraw.