Bitcoin's total value being 2 trillion dollars is not the same thing whatsoever as bitcoin being responsible for 2 trillion dollars of GDP. There is no "merit" here.
We can have $2 trillion in GDP with paper money, too, and that uses 0% of the world's power.
To be fair, paper money requires banks & bank employees, bullet-proof transportation trucks, government regulation, anti-counterfeit research & technology, and perhaps more.
We can have $2 trillion in GDP with paper money, too, and that uses 0% of the world's power.