Gold is also inefficient by design. But it's been successfully used as a store of value for thousands of years. It causes miners to expend large amounts of energy to extract gold from dirt. "Inefficient by design" misses the point because proof-of-work is the feature, not an inefficiency.

I've written about the similarity between gold and Bitcoin here: https://runeksvendsen.github.io/blog/posts/2017-06-14-bitcoi...