So you have an argument for porn being useful (not that I disagree), but you can't find a single reason for why cryptocurrencies would be useful? Or even Bitcoi

So you have an argument for porn being useful (not that I disagree), but you can't find a single reason for why cryptocurrencies would be useful? Or even Bitcoin alone? Bitcoin could adopt a proof of stake system if the core devs and users thought there's no other way for Bitcoin to survive. The Bitcoin ecosystem seems to be very conservative and they only make big changes when they are under high outside pressure. If Proof of Work was banned, Bitcoin would still be here tomorrow, is what I'm saying. Perhaps it's a good idea to ban PoW, but it will not have any significant (long-term) effect on Bitcoin's adoption.