considering that there are many people on the world 
other side who do not have access to a bank card with 
international payment capabilities (visa/mastercard 
etc), they can pay with the local banking system, 
local currency (cash, checkouts or some online payment 
system), and they can use cryptocurrency or any medium, 
or need to add support for so many payment systems 
(webmoney, JCB, wechat pay/alipay/unionpay, prepaid 
/ gift cards
