> Also, one of the definitions of life is "a local decrease in entropy, at the cost of a global, larger, increase in entropy". By this criteria, every living being is a bad thing for the universe, because it accelerates the global heat death ever so slightly.

The discussion about energy use of Bitcoin is within the context of the effectively closed system of Earth.

Until such a time that solar generated electricity is too plentiful to meter and ubiquitous, Bitcoin mining will cause huge demand for fossil fuel based energy, with the associated consequences for climate change.