Actually, GDP is a fairly useless number; particularly for attempting to value a bitcoin.
Frank Shostak explains, "The GDP framework cannot tell us whether final goods and services that were produced during a particular period of time are a reflection of real wealth expansion, or a reflection of capital consumption."
As Ludwig von Mises wrote, "The attempts to determine in money the wealth of a nation or of the whole of mankind are as childish as the mystic efforts to solve the riddles of the universe by worrying about the dimensions of the pyramid of Cheops."
a cup of coffee?