[OfficerGuac]

Bitcoin is usually mined through mid-to-high end graphics cards. People running a pool of 6-7 of these cards per machine are seeing diminishing returns, so using a Pi wouldn't cover the electricity needed to keep it running.

[symmetricsaurus]

Bitcoin is mined using ASICs, and not GPUs.

But, it’s true that mining using a raspberry pi would not be very useful.