Considering the number of people that don't like PayPal and avoid certain types of payment processors, it would be useful if these people had a payment method they used to purchased things on Twitch. GabPay is a popular one that is available in the US and Worldwide shortly. Its fees are half that of PayPal so Twitch would make more money when people subscribe using it over. There are also no charge backs so that is one cost Twitch will not have to worry about.