https://youtu.be/PyQEf_LlbUk Im not joking watch this video, with 3000 mh/s he earns 0.0172 BTC a day, calculate with 15gh/s = around 0.06 BTC a day. Ok if Im wrong, but with 15gh/s should still earn around 0.02 - 0.03 BTC a day i think.. Why people buying antminer with TH of power? because they want to make lots of BTC in one day.