M-Pesa has delivered digital currency on the mobile phone to the unbanked (and banked) in Kenya since 2007, successfully, without exchange rate volatility, and

M-Pesa has delivered digital currency on the mobile phone to the unbanked (and banked) in Kenya since 2007, successfully, without exchange rate volatility, and without burning 15 GW as BTC (for comparison, each of the 4 Chernobyl reactors produced just 1GW).