Our relationship with technology is more immediate, and elements we rely upon everyday are usually represented in lowercase: fire, electricity, cars, lightbulbs, computers, phones, internet, email, tweets. All these discoveries and inventions were new at one point but reached a critical mass of adoption to make them a regular part of everyday communications. We believe bitcoin is at this inflection point.
I agree with the other examples. but I still capitalize the Internet. I think I'll keep using Bitcoin when referring to the network.