A significant part (literal billions of dollars) of fiat used to buy bitcoins went to miners direct electricity expenses, and those extreme amounts of resources were permanently spent, possibly wasted. It's not a zero-sum game, as sustaining the current system costs a lot.
A quick, rough calculation - if ~30 TWh were spent on mining Bitcoin, and the marginal rate of death for electricity generation is at least 100 per TWh (https://www.forbes.com/sites/jamesconca/2012/06/10/energys-d... or https://www.nextbigfuture.com/2016/06/update-of-death-per-te...), this means that we have sacrificed the lives of at least 3000 people to make this happen. Are the benefits worth this cost?