If there is a surplus that is being transformed into deadweight loss, that is a waste, although one can view it is not being inherent to bitcoin in particular. It seems to me that, at least to first approximation, we should expect the seignorage to equal the market value of the currency, the market value to equal the net present value of the expected future value, and the future value to equal the surplus value generated by the currency. Which would suggest that it is a wash; resources are being spent in the present to create a currency that will create surplus value in the future. But then perhaps there is surplus value that isn't captured by the holders of the currency, which makes the currency a net benefit for society. Or maybe there are costs that make it a net loss. I'm not confident in my economic understanding enough to be sure what the overall effect is.