The main use case for block chains is quite obviously to skirt government regulation: black markets, unregulated securities and quasi-securities, etc. A secondary and related use case is to avoid the hassle and complexity of old fashioned equity and other fund raising constructs and to make easier international wire transfers.

Putting ethical concerns aside: these are very large market segments. Cryptocurrencies may be overvalued but there's definitely a real use case. It's just not a use case that governments, banks, or conventional VCs like.

I feel like all the claims to the effect that cryptocurrencies have no use case are ignoring the obvious.