Block co-founder and CEO Jack Dorsey led a $6 million seed fundraising round for Bitcoin payments firm Azteco, the startup announced today. Azteco provides a one-of-a-kind option to buy Bitcoin globally, with a focus on making it easier for unbanked communities to use the digital currency. Users can purchase an Azteco coupon online or in person, which they can then redeem for Bitcoin. The model operates in the same way that purchasing a gift card or a mobile phone top-up does. This option gives customers more flexibility because they do not have to go via an exchange to buy Bitcoin in their native currency.