As a payment gateway to what exactly? Mind elaborating on this one? If you mean making business with bitcoin, that's what companies like BitPay and CoinGate are already doing. They receive payments in crypto and instantly convert coins to fiat (dollars, etc) which merchants accept as payment for their goods. If you mean accepting crypto for public services, it is unlikely to happen any time soon since this effectively means accepting cryptocurrencies as legal tender (with which you can pay your taxes). Well, at least not a very far cry from.